I'd also say weaken the light a tad and speed it up a tad.
We know the heavy is as fast as it is in T1 (Thrax has said so numerous times, that it's about the same speed). And we know the light is lighter than a T1 light, and faster. Maybe use the renegades Super-Light?
and Pyro, like I said, if you're in Light you shouldn't be fighting. and if I was in light, and fighting, and my opponent exploited my weakness, unless he had the flag, I'd probably move away. If he did exploit my weakness by taking to the air, I'd gren spam (if we have grens), try to MA, or, try to cut him off. He has to touch the ground at some point.
And yes, I am specializing the light. The light should be a specialized armor, not an all-rounder. The medium should be the all-rounder. The light should be a specialist, and the Heavy should be what you call when you need a show of force.
Oh, and if I knew how to code I'd help with the T1 Vengeance mod, but since I can't, put me down for trying it out