The heavy overpowered? What is he now?
The pyro is supposed to be the one who's best up close and personal. But the heavy makes him cry if used correctly. His melee is the most powerful excluding the spy's backstab. He also has 300 health, which is a lot without a medic. The only sure way to kill a Heavy with a medic is to head shot him or back stab, unless the enemy team is concentrating all their fire on one Heavy.
His gun's range is relatively medium, which means Natascha will just hamper the entire enemy team. Valve will probably take it away after the constant whining they'll receive about how broken the Heavy is (remember the pyro?).
I don't think the heavy is OP compared to a lot of the classes here.
Pyro is supposed to be the best when up close and personal. And he can make any heavy turn into bacon if used -correctly-, just as any heavy can blast a pyro if used -correctly-. The misconception people keep bringing into this is human error and personal preference. If everybody did everything a specific way all the time, or the right-way all the time, your going to have issues anyway, not to mention a boring game.
A large part of any FPS is waiting for your opponent to make a mistake.
I myself am a decent heavy, at least in personal opinion, but that doesnt mean I don't die a lot. crit rockets, headshots, demo stickies, pipebomb spam, spies, all of these things take down heavies quick, medic or not. People seem to be forgetting that the heavy is the primary tank class. Of course you aren't going to be able to take him head-on by yourself without an advantage of range or backup. that is how tanks are designed. And lets face it: If an entire team is dumb enough to chock itself into a tiny hallway, and dont have an uber ready or going, they deserve what they get for that mistake, be it from heavy, stickybombs, or critrockets.
If you're being dominated by heavies left and right, you either need to change your tactics or avoid them if you can, whichever suits your class' best interests. I take down heavies all the time as a soldier, I make it my job to do so.
The final point is, none of these new weapons are going to make the heavy a massive threat to the game. Natasha makes the heavy even more defensive than Sasha does, meaning hes going to be poking around corners a lot. Howeve, a lot of players that use Sasha already use this tactic when playing a defensive heavy. If you are a scout, you try to avoid confrontation alltogether, at least if the intelligence is your motive. Medics should hide behind their meat-shields, and travel in groups. If either go into a hallway alone or just go in blind, they deserve to be shot to death. Just as any heavy that wanders into a wide-open space without company or at least a medic deserves to have his skull turned into a pudding bowl.
Powerful? Yes. Overpowered? Hardly.