I've tried MEW 9.10 on a recent WINE and now on a CXO 5.0.1 with the same results.
Show stopper:-
The cursor location and the text location are not the same. That is to say you type something and it appears somewhere other than where the cursor is.
Earlier versions of MEW on earlier versions of WINE didn't seem to have this problem.
Serious usability problem:-
Crashes when you try to use customise. CXO gave me a dialog first time, but now does same as WINE, ie shows first part of the dialog and then just hangs.
I really like Multi-Edit and I'm not the only one who wants it to work on Linux. I am considering becoming it's advocate.