Sooooooooo your team won't change what they are doing even if they are getting blown out of the sky? Well what else can be said but be water my friend...
Trying not to be mad (Vette issues)
A single properly flown corvette is fairly game changing as they can pick off the healers pretty fast, and take the focus off the rest of the team, and so maneuverable. Stealth isn't so huge (but certainly an advantage), once you get used to them, you can spot them (I haven't seen if there's a more powerful cloak, but as far as I've seen, the area around the ship and the ship itself, light is distorted)
Also, if your playing in a PUG vs a team with voice, you will be in for a challenge. I don't know how to tell that (I wish there was like a coloring or something so I knew and could drop out or something) IMO, I think that the game should match higher level PUGs with lower level pre-made teams. (There would have to be a lot of testing here, is 2 players enough to constitute a team? If it's just 2, do we place them against the players 2 levels higher? why not 3? How does this affect queue times? -- This is a whole different thread.)
IMO, corvettes aren't meant to be frail, if your a fan of star trek, I think more like the Defiant Class of ships. The Defiant was the first dedicated combat vessel, carried ablative armor, and, was also the only federation ship to feature a romulan cloaking device.
That said, I believe that maybe corvettes shouldn't have Damage Block shields.
+1 for the Bruce Lee reference
This all sounds like a MM / teamwork issue honestly.
OP they very likely will not ban certain comps in PUGs, if for no other reason than the fact that it could screw players who only have 1 or 2 ships in their loadouts.
As for vette's... I recently got my hands on the Talionis and I regularly chase them down and blow them away (in PUGs), it is the most satisfying thing ever. Especially since I can turn around and warp right back to my place in the formation (Talionis should have been called the Outrider).