I'm sure there's already a Genesis Plus GX thread, but it seems like it would be a bit of a necro to bump it. Judging by posts here, it seems like many people don't even realise that there are official SVN builds later than the official release.
https://code.google.com/p/genplus-gx/source/browse/trunk/builds
r932 added WiiU Pro Controller support.
https://code.google.com/p/genplus-gx/source/browse/trunk/builds
r936
"[Core/SCD] disable access to mirrored areas of PRG-RAM as well when SUB-CPU is not halted (continuing fix for Dungeon Explorer USA)"
r932 added WiiU Pro Controller support.