As one of those people who have recently switched from TextMate to an older editor (Emacs, in my case, even though I used to be a vim bigot) I’ve been following the blog discussions about it with some interest.
I don’t have a lot to add, other than this: read phil’s post and then read these slides about what UI designers can learn from game designers and see if anything clicks.
Oh, and read al3x’s thoughts too.
And then see if you start thinking of an editor that looks like TextMate, starts out like TextMate, and then over time gets bent and prodded and poked until it becomes more like Emacs or vim, or both, or something new altogether. An editor that adds tools to your toolbelt as you progress through challenges and learn new skills.