WxWidgets is not really a problem. My problem is the version that is used (2.9), which is considered unstable by many distro packagers (although the WxWidgets devs say it isn't). On the other side, as far as I know WxWidgets uses gtk under Linux for drawing the whole stuff and makes it for the bitcoins devs easy to make things cross platform.
wxWidgets 2.9 is their first UTF-8 version. We are UTF-8 on all platforms including Windows.
The distro packages of 2.8 are UTF-16, so they just trip people up. People had endless build problems with 2.8 and its wxString UTF-16/ANSI conditional build options until we standardized on 2.9. Also, to use 2.8, we were using ANSI, which was just a temporary stopgap until wxWidgets supported UTF-8.
This is a problem that will solve itself. With time, 2.9 will become a more mainline release.