Just because you play against terrible players doesn't mean you know what you are talking about. You know what would have countered those mediums a million times better? Shreks. You know what does well against IS2's? The Panther, Jadgpanzer will also do work.
Stop trying to sell people this retarded bullshit that just because you beat a idiot using them, or got insanely lucky with penetration that the Puma is worth 70 fuel at a reduced income when could be spending that fuel on something that has a lot better transition mid to late game.
Just because you don't have a clue or skill how to use a unit it doesn't mean its under performing.
Stop creating problems where there is none. I play 1v1 and 2v2 only and I can see how in large team games Puma would be neglected due to increase rate of tech but this shouldn't compromise the balance of more relevant game modes.
Edit:
Also I like how you assumed I play against bad players because I don't know why. I guess that's what you do when you run out of counter arguments.
I play against players that are so bad they would flood you with Shermans and T-34 when you would try to stall a game waiting for Panther.
I'm not saying I go Puma every game but when I do I get my moneys worth.
Last time I checked I was around 1000 elo 2v2 as OKW. I haven't played for a few weeks now as I'm waiting for new patch but since meta has been stale for almost 3 months I don't think it matters.