While it has not changed gameplay, it certainly has changed the player community. A lot of people play /just/ for the hats and are obsessive about it. Eventually people who don't care can get annoyed with all the bitching about pointless accessories.
Being around since when the Pyro got his first set of unlockable items, i've gotten used to how things have changed, and i've not complained once about the store, the trade servers, or people constantly looking for items, i've only complained about idlers, but that's their choice of how they're gonna obtain items, so i've gotten over it, any bugs/glitches that are fun to abuse (e.g. Civillian) that gets fixed, i may be a bit sad over, but i get over it instead of complaining
I just think people exaggerate/take things too seriously :/