yes, heavy is underpowered in some ways, but in unorganized 12v12 pub nonsense a Heavy / Medic combo can still rape.
I agree that with relatively slight buffs the heavy could be a contender in small comp-level play, but I think those buffs would make him much much more brutal in pub play.
It's the reverse of the issue with the scout. Most comp players wouldn't mind if the scout was nerfed a little, but any reduction in his power would make him even WORSE for the average pub player.
With all that being said. the quick switch to a shotgun wouldn't make him THAT much better in Pubtard play, and would I think help him a good bit in more organized play.
he's essentially the WAY slowest class right now, cause soldier's and demos move across open spaces at rocket / sticky jump speed. That speed itself is a liability.
I'd like to see what a speed buff and a quicker cooldown on the rev would do to the heavy.