The hate is very, very simple.
The game, prior to 2.0, was more broken. The AI wasn't good. There was no optimal way to win. Even if you screwed up hard early on, you could always doomstack at the end and still win. This meant that you could really do basically anything you wanted. You could roleplay any civ you wanted, in practically any setting, and there would be no real "consequences" beyond "now it's harder to win". As long as you could always doomstack at the end, you couldn't lose. The different types of FTL gave more options early on, too. As a player of 4Xs, I'm sure you know quite well that the earlier something happens in a game, the more difference it typically makes. Same for FTL.
Removing FTL and trying to "fix" the gameplay meant fewer "options" were viable. It became less of a screw-around-sandbox and more of a 4X. People that liked it before because it wasn't
a 4X (myself included) simply don't like it now at all, because they don't like 4X's, and I think you'll agree that it's just a matter of preference and that's fine.
In short, people are upset because now the game they loved has morphed into something they don't. The game is more "fixed" which makes roleplaying more difficult. It's less of a sandbox, and more of a 4X. These are not small changes. This is an entire genre shift. There's no reason to be surprised about the hate. It's really, honestly, very simple, and they should have expected it. They probably did. Fact is: the devs didn't care. The new guys just want their own game, even if it didn't mesh with the perceived vision of the original. And therein lies the problem.
It's important to remember that just because you
think gameplay is better, it doesn't mean it's actually better for everyone. Especially
if there's a genre shift involved.