I could do a full page bullet point thing, but the straw that broke the camel's back for a lot of people was that they fucking powercrept every character almost instantly, and not by like 5-10%. New element characters were into the millions of damage more than old ones, etc. Their balance was terrible and basically boiled down to getting carried by whales in all content. While that might sound fun if you're lazy, I assure you it wasn't fun for long. Then instead of doing any number of things to make it right, they just spun off a brand new server called the renewal server or something, where they started you from the beginning with story/balance refinements, making the game a lot more pleasant, but none of your purchases/rolls carried over, not even the cosmetics.
Then 2 months later they powercrept the hell out of that one too. Just laughable ineptitude at a dev level.