I have seen 'vettes dominate in one match, ever. I mean, really, really dominate, to the point where my team simply had no hard counter. There were 5 of them on the OPFOR. And we still got kills on them and put up a fight, and it was a fun challenge to do so.
Every other match? 'Vettes are fodder. If it's not a player name I recognize, I assume it's just a treat, for score padding. I've killed 'vettes in Dreads, Dessies, obviously TACs, and even Arty with the main gun(med & light arty). Here's the thing: I'm not that good of a player. I'm average, upper-end of average maybe, and I've never, even for a second in this game felt that Corvettes were anything but balanced.
Now I cannot for the life of me play Corvette all that well myself. I've had a few good matches, but overall I don't enjoy the playstyle. High risk, low reward, very little room for error, and every player on the other team, especially their TACs will have a permanent hardon for you. I commend the guys that can main 'vettes and do so successfully, while having a good time.
I think 'vettes are in this game to teach newer players situational awareness, which tbh, they should have learned in all the other games they played growing up as a child as most of us do, or in you know, real life. But hey, some people are more tunnel-vision types, and it's them that the 'vettes are there for. You cannot have tunnel-vision in a game like DN, or most online PvP games really, 'vettes are just there to remind you to get your head out of your rear and focus fire. Start paying attention, and start watching 'vettes melt, it's that simple.