This is nice, as a notion, but flies in the face of canon, where recon elements track down enemy destroyers all the time (the Ravana, the Vindicator, what have you.)
Utterly disagree. The fact that ships manage to stay in the same system and NOT immediately get blown to hell means the exact opposite to me. Consider the NTF conflict where the GTA KNEW exactly what systems the NTF had ships in, but couldn't immediately wipe them out until the Colossus arrived, and we can reasonably assume nearly all those attacks were offensive operations against hard targets (shipyards, instillations and nodes).
The Hecate's advantages are all nice, in theory, until you realize that space is tiny in FreeSpace, because subspace; and ships rapidly and routinely get vectored to their origins, because subspace tracking; and that makes a carrier that can't defend itself a problem - as we see twice in FreeSpace 2, where the best the Hecate can do is run.
Subspace tracking, everyone keeps talking about it, but I don't recall a single moment outside of the Lucifer attack, through inter-SYSTEM subspace, that subspace tracking is ever used or even mentioned for that matter. I'm just not seeing it. Can the Shivans do it? Maybe, but I don't see any direct evidence of it. They could just as easily use their large numbers to basically spam scout a system if they have to, and frequently when the Shivans do launch such a strike, it's to the most static location in Freespace: Jump nodes. And if the Shivans are sensitive to subspace, they probably FEEL jumps through the node more often than not. No need for tracking at all.
Subsapce drives. Charge time. Important elements that need to be taken into account.
The carrier offensive power lies in it's bombers. Bombers take time to launch, to reach their target and lock on, bombs have travel time and can be shot down. Beams have none of those issues.
Consider a battleship ambushing a carrier. . .
Next, consider a carrier ambushing a battleship. . .
We actually don't know charge time, not really anyway (it basically varies from mission to mission). If we had hard figures we could do more with it, but we don't, so we can't.
Your argument about bombs and time to launch is fine, to a point, but also it comes down to risk. Bombers are cheaper than battleships. I'd rather lose 20 bombers and only just damage a target than lose an entire battleship to do the same. Also once a BB goes into battle, even if it wins against another one, it will have to go in for repairs. Which means it isn't on the battlefield. Losing some bombers for a carrier doesn't strictly weaken the carrier's ability to engage targets, it may not be able to take on another ship, but it can still take out raiders, scout, attack supply convoys, intercept other carrier bombers, and with the right weapons can even cripple opposing ships and instillations. It's more flexible than a battleship which really can only attack other battleships.
Again, we don't know enough about drive charge time to make arguments about how battles should go, but we do know one thing: If a carrier is jumped by an enemy, it likely knows where it can safely go because it has fighters to scout the region for it. A battleship does not. The BB thus is more likely to have to stand it's ground as it doesn't know if where it's going is safe, where the carrier can run safely.
We also aren't considering that there are other ships on the battlefield. Cruisers can screen fighters, Corvettes can directly engage the battleship with fighter/bomber support, we don't know about scouting, reserve forces, the carriers CAP, the actual energy needed to support beam cannons and how that effects jump drives, ect, etc, etc. Freespace provides far too many unknowns to allow us to really know how these battles go.
All that we can say is that from what we see from the Hecate is a carrier designed to stand off from it's targets and the Orion and Hatty were more designed to directly engage. It's about combined arms against an enemy that outnumbers and outguns everything they have. You need to be flexible to take on these kinds of foe, and a dedicated carrier provides this. A dedicated battleship isn't nearly as flexible, even if it is effective in a single area.