They're supposed to be challenging, after all. If your wingmen are getting killed, don't just C-3-9 all the time. You know you're wingmen can't handle themselves, so C-3-8 to keep them together and close to you. And if you really want them to survive, try to protect them yourself.
Or, play on Insane, the way the game was meant to be played. So you'll die before your wingmen do, and if not, then you'll learn how to play the game better.
It's all simple tricks and common sense, keep your wingmen together, avoid flak if possible, stay near friendly capship flak... it "only" took me three tries to beat the last mission. Use those harbingers!
As for a Shivan briefing, the FS2 tech description implies that Shivans are basically machines. The ones we saw in Hallfight might not even be "normal" Shivans, but a special type of hand-to-hand combat unit with an exoskeleton. So the briefings would be straightforward instructions, like you'd give to a machine. "Four wings of Terran bombers are incoming. Destroy them. X and Y wings will support you." If not that, then the campaign would take place from the perspective of the Shivan hive-mind, and the briefings would be little more than a situation update.
