I'm a bit late to this discussion but I agree that the GUI of Hatari is not very user friendly. But the emulation is great. It at least support 0-byte lines that Steem lacks.

Of course a MS Windows GUI could be made for Hatari but I think a better idea is to make a GUI in QT. The QT library is freely usable and has implementations for many platforms like *nix, Windows, Apple and even mobile devices.
So if Hatari uses QT, it could have a nice and fast GUI while still being cross platform.

Robert


QT library:
http://qt.nokia.com/products/