Bottom of the list is: - functionality - native look and feel
What's "native look and feel" doing at the bottom of the list? IMHO "native look and feel" is a prerequisite for any Macintosh App that is going to be accepted by Joe Mac User. So if Joe Programmer wants Joe Mac User as one of his customers, he'd better go for native look and feel.
An internal goal (irrelevant to Joe Programmer) is that the Haskell-GUI-library design should be high-level enough that it can be implemented on top of more than one underlying non-Haskell GUI library. That is a worthy goal, but the discussion I have seen has made me conclude that it is simply too difficult to meet. Let's abandon it!
I didn't reach that conclusion from the discussion. I still believe it's possible, I only reached the conclusion that a mailing list discussion doesn't work too well. The issues at hand are much simpler than the discussion about them.
Joe doesn't care. I think it'd be fine to pick *one* library (Wx, Motif, X11, Tk, whatever)
Wx at least tries to provide native look and feel (with limited success on Mac OS so far); we might just choose Wx and hope that the Wx folks will one day fix the deficiencies. A Haskell GUI lib based on any of the others would be next to irrelevant for Mac OS development (no native L&F, perhaps even a separate X11 installation required). So I'm still in favour of platform-specific backends; but I wouldn't protest too much if we opted for the Wx option after some more discussion. Cheers, Wolfgang