Ruin
Golem
Fishing, Daedalus Stormbow, Summoner being worthless early and overpowered late, Mage being all-around sub-par, all flails being completely worthless, the ability to easily run into the underground jungle/corruption to get weapons that are way better than what you're supposed to have, pre-hardmode ore armor sets requiring 90 bars (!) just for a single set that gets overshadowed by better armor almost immediately, Old One's Army T3 being insanely hard for when it's unlocked and the items already being underpowered by then, expert Frost Moon being harder than the lunar event and with worse rewards, Fossil Armor being useless by the time you're able to get it, and Meteor Armor + Space Gun making the entirety of pre-hardmode a joke, among other things I don't feel like listing right now because I've gone on long enough.
I would heavily disagree with some of those. There is nothing wrong nor broken about the player having the ability to sequence break. The Jungle is a rough place, if you're a good enough player to brave it long enough to craft an Amazon, I think you deserve to use it.
And yet again, there are those two "items" that everyone and their mother love to scream "OP!"; Daedalus Stormbow, and Space Gun. I simply don't understand the rationale. The Stormbow is an excellent weapon, but highly inaccurate and with a habit of swallowing stacks of arrows whole. I don't see how that's remotely overpowered.
The Space Gun? It's only useful while wearing the entire Meteor Set. It's damage barely increases and it's the only weapon in the game to get a bonus that removes it's entire cost, Mana or otherwise. What's wrong with letting something remain unique? There are much better weapons than the Space Gun in pre-Hardmode. There is a difference between powerful and overpowered. Something I think a huge amount of people, this forum or otherwise, need to realize. That mentality is what destroyed the Spectre Set years ago. I will never forgive that.
I don't really agree about fishing, either. I mean, it's only the most dull thing you could spend your time on. It might as well give you something worth your insane levels of boredom.
I suppose I agree about Summoner, Mage, Flails, Early Armor costs, Old One's Army (I'd argue this is awful overall), Frost Moon (I'd also argue that both Moons are dreadful), and Fossil.
I'll leave it there to not derail this thread.