If the Kritzkrieg was released in 2013 instead of in 2008, it would be banned in a heartbeat, because it wouldn't be what everyone would have been used to playing against.
People afraid of change would call it OP and scream for it to be banned in threads much like this one, and most people would follow suit because most teams wouldn't be able to come up with a solid way to counter it before the next season.
They would talk about how maybe it would be better off if it charged at the same rate as an uber, since you can, according to their theorycrafting, surprise and uber-running team and make the medic drop easily, or maybe about how crits that did 2x damage would make more sense. People would talk about how it would slow the game down, since teams would be afraid to go into mid quickly or risk getting kritzed on. And a paragon of weapon balance would be shelved and condemned to be used in pubs only forever.
That might be unthinkable now since everyone knows how the Kritz works and how to counter it (and prove the above theorycrafting completely wrong), but that's because we've been playing with it since the dawn of the metagame; most of us found out about it while we were still new to the game and playing pubs. The Quick Fix, on the other hand, is completely new, and people are scared by it. Wait 2 seasons before closing the book on this interesting new strategy, and people will learn how to adapt to it, probably for the better.