Everybody hates all serious 3d application interfaces… they’re just complicated. I’m professionally competent in Houdini, Maya, Max, Blender, Zbrush, Marvelous Designer, the UE editor… they all suck in various ways but it’s all a giant set of trade-offs and priorities. Beyond that, lots of these programs have lineages that go back decades longer than almost any modern dev environment and being so complex, UI changes can be quite disruptive. A lot of (no, not all) developers think they have the most complex tooling in the computer world — they definitely don’t.