Slammers, armor coagulant and active armor (though the GTVA seems to already have the latter), the Scalpel, PAVEWAY, Shrike, Archer (and the Uriel-gunship, at least its role and general capability; a wing of Uriels might be able to actually disable a Sath's forward beams given enough time and some cover), REDEEMER (and, if made more practical, the Vajra), beam jamming if actually effective against Shivans, Burst Flak, Point Defense Turret's (works great against warheads, decently against fighters/bombers, and does a little damage to other ships with accuracy), and the Narayana.
Narayana...now there's an interesting one. Its mass drivers and gauss cannons are actually powerful enough and practical enough to be a decent Sathanas counter. With a sprint drive, more gauss cannons/mass drivers in place of the torpedoes, and give it some AWACS support, and you've got a pretty effective (if niche) platform.
And the Dart. And the Dirk. The former for obvious reasons, but the latter for its effectiveness against unescorted bombers and moderate utility against larger targets and fighters as well. Though I can't remember if the Tornado does similar damage and has similar cargo size...because then the Tornado would just be the obvious winner there.
The Grimler is just...I'm not sure, but it just seems too similar to the Trebuchet but not powerful enough to make up for its lesser range (and larger cargo size?).
The Durga bomber, if made cheaper (likely through reducing maneuverability, some secondary capacity, and other non-essentials; maybe just make it a Redeemer and Warhammer platform), may be a viable heavy bomber unit. Redeemers aren't limited by the stupid aspect-lock, refire times, snail-like speed and interceptability of bombs, so they're actually much more practical. And they're better against subsystems, too.
As far as primary cannons go, aside from the Scalpel (and not counting the Redeemer or Archer), it's hard to justify taking anything over the Balor (or an updated version of the Balor), with the only possible exception being the Rapier. It has enough punch, ROF, range, and not too much energy consumption to be practical for space superiority and SOC operations.
The Custos is somewhat interesting in one aspect--if it can affordably house decent AWACS capability as a standard, alongside its other standard armament, then it could be a cheap, effective, and versatile asset to be used alongside groups of fighters/bombers. Not just fire support against craft and ships alike, but limited AWACS capability, major boon to convoy escort (warhead interception, Warhammers against cruisers, AWACS, etc.). The Cretheus is still far superior against craft and ships with lighter armor, though, on top of being significantly smaller (and probably cheaper, too?) and having better turret coverage.
The Sanctus cruiser/corvette is an interesting notion in the sense that, if cheap enough to produce/use, could effectively double as military freight, transport, convoy escort, antipiracy duty, and major supporting roles in wartime operations.
The Karuna Mk2 is also rather interesting. If it can be constructed (and operated) under the cost of a Diomedes, it would seem like a worthy replacement. The normal Karuna, though, is just plain impractical and innefficient in most roles outside of Sol. Unless antipiracy duty would really benefit from a few Karunas, it's hard to imagine it being useful outside of a fire support and minor carrier capability.
As for the Solaris-class....well, the key is how much it would cost to construct even a watered-down version. But as far as potential goes--large carrier, sure, but imagine if you converted it into a massive SSM platform. Just...think of the possibilities. Slap a sprint drive on there, pair it with an AWACS, and you've got insane levels of SSM artillery available in whatever system it's in, along with the fleet-carrier's worth of strike craft it brings along with it.
Oh, duh. Of course.
Man, that gun. That's how you make the Draco practical (if even more niched); this gun is pretty damn impressive when used correctly. And it doesn't even use ammo, making it practical (I think) by GTVA standards. The UX Accelerator is also a great weapon, but being an ammo-based one that requires a decent amount of skill and getting used to, it's probably less likely to get adopted.
Ah, right. The Lapith. A very interesting craft. Practical, beautiful, and fairly versatile for a bomber. If it has/could be modified for adequate endurance and affordability, this might be the ideal mainstay Terran bomber--even if you'd run escorted formations of two or three instead of four, it'd be much more effective regardless.
The armor coagulant is a brilliant piece of tech--if it could be affordably/practically applied to GTVA ships, it would be godsend. You could send a ship to a fight that you're confident it would win, and then have it repair itself by a major degree in as little as a minute or two of lull in the action. Of course, it wouldn't be a true substitute for dedicated repair time in dock, but it would save tremendous amounts of lives and assets, while boosting overall combat effectiveness and morale.
Still waiting to see the Arquebus in its intended action; depending on where its mounted and its final stats, it may or may not be that useful.
The Hydra...well, an interesting weapon at least. Not sure if it's that practical against Shivan forces. I'll wait until we see it in action to judge.
The Vindicator...I'm very curious as to what this is, exactly. Seems to be a ship or craft of some kind, but it may also just be an outdated name for an existing ship, or a craft/ship that got cut.
Hellfires....not sure if it's worth adopting over the Tempest.
The Oculus might be a better electronic warfare platform than the Charybdis--it's probably much more expensive, but having a small number of them may be handy for dedicated beam jamming. If the design and capabilities were entirely dedicated to beam jamming, its potential against the Shivans may be worth looking into.
The UEI Kumari, as well as the UEI Bretonnia, seem rather practical and useful.
The Vajra fleet bombers might be useful if the design could be adapted to a dedicated anti-beam-cannon platform (pretty much for use against Sathanas Juggs), and made cheaper, likely forgoing most of its secondary capacity, and a bit of maneuverability. Its Vajra cannon, if it could be adapated to a more Archer-like role and performance, might make it practical.
The Izra'il assault fighter is an interesting and powerful craft, but its practicality beyond Sol depends on info we just don't have yet (cost, flexibility to be modified for more practical GTVA roles, if it could mount Maxims ( >
.) without much trouble, or Archer-like cannons, etc.).
UEF probably has some useful terraforming tech, come to think of it.
As for why beams are better--even with the heat issues, it's undeniable that the shear damage output, accuracy, general range, and field of fire makes beam cannons a vastly more preferable option than all but the best mass driver setups (when it comes to killing ships). Even a Karuna Mk2's damage output, with its sixteen mass driver cannons, is roughly equivalent to an MBlue with a refire time of 10 seconds, maybe with an SBlue thrown in. Definitely respectable, but compared to even a Chimera, it's relatively weak (and nowhere near as practical for shock-jump tactics).
And as far as torpedoes go, it just seems like they're a lot less effective and practical as a primary armament than beam cannons, especially because of how easily they can be intercepted by diligent fighters or good point defenses. It works well for the UEF because they've got a giant stockpile of antimatter torps all ready to go, so spamming them isn't nearly as expensive as it might otherwise be. Even then, though, just ask the Akula and Ranvir how much their torpedoes helped in the face of beam cannons, especially from a distance greater than 4 km. It does good damage over time, but against the Shivans that's only useful as a secondary/followup armament, not a main one.
Hopefully the UEF has some good construction/applied sciences that can make the production of ships and craft cheaper and/or faster for the GTVA; it's far better to have three Chimeras than a Bellerophon if you can do it for equal cost and time. And the Shivans seem to have lots and lots of ships. Almost ludicrous numbers, if AoA's Shivan/Vishnan warfare was only indicating a minority of Shivan forces (though why they'd make anything other than Liliths, Sathanas's, and maybe Demons is a tad puzzling. Then again, Liliths are absurdly and jarringly OP, given their corvette-level hull, decent point defenses, a freaking LRED, all in a Cain-sized and proportioned cruiser---seriously, wut? Why even bother with building Rhakshasa's if you can build a Lilith, even at double the cost? And why is the Ravana the epitome of a glass cannon in order to mount two LReds when you can feasibly mount them on cruisers with the durability of a corvette?).
Okay, wrapping up here. The Ainsarii--not enough info. If it's affordable enough, it might work as a niche unit for the SOC, where you need both stealth/recon capability alongside good combat capability. If its stealth and recon capability is leagues better than the Pegasus, then it's a whole 'nother ball game entirely.
Lao Tze--yyyyyeah. Don't really see the appeal for this fighter. It's huge, its gun placement is poor (except for its Cavalier pair in the nose), its secondary banks are oddly positioned and very picky about what you can put in each one, its speed is merely equivalent with the Draco and Kent, and its maneuverability is--while great--not enough to make up for its huge profile, awkward gun placement, and obvious expense for a role that could be just as effectively performed by a pair of Kents or a wing of Nyx's. And in the face of a wing of Atalantas with Balors and Tornadoes, I'd rather be in a Kent (so I could run away...and lob missiles at them while reverse afterburning).
Angel Flares...still no info on how effective, affordable, or practical they are. So wait and see.
Ah, and one other thing. An Archer variant (or just different ammo) that is effective against bombers. Though it would lack the range of a Trebuchet, being able to carry 70 rounds at a time, with a refire rate of one second, certainly intrigues me. Against unescorted wings of large, slow bombers, getting within 3 km and lobbing shot after shot until each of the four are down (or in total disarray) has a certain kind of appeal.
And whatever needs to be done to increase the max range of the Balor. Not its velocity, just its range--to make it a better anti-warhead tool against waves of lumbering bombers. And, well, a slight increase in damage in exchange for a small increase in energy consumption wouldn't be at all unwelcome.
//sorry, I'll end this stupidly long post now.