Hi, just recently started playing TBP too.
I remember that mission; it struck me as very hard too. In my previous experience in Drums of War, taking out Sentris in a Frazi was challenging, but not impossible - when you have a 75mm pulse, one shot and they're toast. Even if outnumbered, I'd take some damage, sure, but generally come out on top eventually. In this particular mission, even with the advanced thunderbolt, I would get ripped apart in seconds. I had the feeling I was easy to hit and destroy, and the one gun you get, even if quite powerful, requires you to stay on a target for a few seconds - and with 3+ enemies on your ass, that's easier said than done. I had dozens of failed attempts, so I thought I'd try to emulate a 75mm-toting Frazi with EA hardware - a Badger loaded with 6x40mm pulse guns was the closest. And, sure enough, I eventually made it. Being able to blast those Sentris with one or two decisive shots, all while bobbing and weaving was the key. Still took a few attempts, but it was clear that was the "right" way to press on.
I agree that wingmen are none other than a distraction, really. Hopefully before they all die you'll have taken out a couple fighters so that you can manage the rest on your own. Missiles are also, IMHO, very unreliable.
What felt really tense and deceptively hard was disarming the ship. It's bristling with turrets, yet with a relatively fragile hull. To disarm it without destroying it you really have to shoot the turrets and only the turrets, which are pretty damn accurate and outrange you to boot. I can't remember exactly, but perhaps if they're on the brink of destruction they'll surrender anyway even if they're not completely, but just mostly disarmed.