I honestly miss classic TF2. It's not that I don't enjoy the new weapons, but whenever I have to tell people to stop spamming trade deals over and over again because its clogging up the chat, yeah. I don't like the trading mechanic, but I do like some of the new items, such as the fish.
What I really hate is the polycount pack set bonuses. Why should I not be able to headshot somebody just because they have 30 dollars of disposable income I don't. I think its complete BS and should be taken out of the game. I wish we could go back to classic TF2, but like any other thing people get used to, try to rewind and people will just get mad.