Probably one of the best thing VALVe has done so far. What's even more awesome is that they added a competitive section to the Beta forums.
The Natascha fix(The 3rd one) is probably the way to go honestly.
Wrangler needs a fix on the shield.(Remove shield completely while the sentry is down, bring dmage reduction to maybe 50%)
Sandman is lost and long forgotten.
Give some love to vanilla melee weapons(Fire Axe, Bonesaw, Shovel) by giving indirect buffs to them.(See Blutsuger and Needle Gun for reference)









