It's possible that you've just explained it: The people for who it became such a problem have already migrated away.

I don't have any numbers for that, but even if it's a small shift, then it could be that most people weren't too fussed anyway.

We as humans and programmers are creatures of habit, Unity by being a relatively new technology will break some habits in our work ritual. Give it a few years and nobody will complain about this.

I don't think Unity is simply different. At least as of 11.10, it was different and objectively worse.

So the question is, has 12.04 made a leap in the right direction, enough for it to be at least as good?

I found Unity awkward at first, but I put in a few days' honest effort to learn to shortcuts and try to work as the designers intended me to, and it improved my desktop efficiency quite a bit, and removed a fair bit of clutter compared to Gnome 2. I like Gnome Shell too for the same reasons.

That said, Unity was buggy in 11.04, and only somewhat less so in 11.10, and I still find myself having to occasionally escape to a terminal and restart Unity after it freezes up. I'm hoping 12.04 is better.

Also workarounds are found and created over time for stuff that is broken or annoying.

That's a good insight. Being as fickle, I may indeed be back to Unity at some point :)