Man, have you seen the GUI for OpenEmu? Completely wipes the floor with RetroArch, despite (in my opinion) being inferior to RetroArch. Needs some graphic designers and dedicated GUI programmers badly.
Those people don’t understand that clobber (part of OpenEmu) works together with us and that we share codebases and cores (well, it’s not as clear-cut as XBMC which just uses libretro cores verbatim - OpenEmu takes some of the libretro cores, modifies them a bit to have them fit into their framework and then it works as such in their framework).
Here is how I see this panning out -
Things like XBMC are going to become the ‘new frontends’ for the GUI fetishists - RetroArch just supplies a MAME OSD-like system (RGUI in this case) and that’s it - if you want more than that, have your own frontend hook around RetroArch - there are plenty of opportunities to do that.
I really don’t see anything like Qt/GTK+/Aero/whatever kind of widget thingy having a long shelf life at this point -you can see on Linux already that things like KMS are starting to gain more and more traction, and on Android/iOS/Blackberry/whatever - none of these ‘widget’ frontends would really work out or be ‘portable’ enough.
On consoles we have no choice and we often have to write our own GUI system from scratch - RGUI comes originally from the Wii port and it’s the most portable GUI system so far. The PS3 has its own ‘frontend’ - RMenu (which I’m trying to mimic now as closely to RGUI as possible) - and for Xbox 360, I use a GUI interface pre-supplied by Microsoft (XUI) - I call this one RMenu XUI. The iOS port has some kind of Cocoa interface but you can still access RGUI all the same.
The problem with all of this stuff is that it is hell to maintain and that the GUI codebases can quickly get out to date and need constant patching up whenever you decide to order something around differently. We have been spending quite a few weeks now trying to bring RMenu (PS3/Xbox 1/Xbox 360) and RGUI (Wii/Android/iOS/Blackberry/PC) closer together and still it’s a lot of manual labor everytime to ‘add’ something. You can’t really understand until you place yourself in our shoes and have to deal with this stuff.