Just thought I'd weigh in with an opinion. ;-)
This would suit me:-
Being able to launch an application in the emulation by double-clicking an icon (even if it's just an alias rather than the app itself) Emulated programs could all be run on the emulated screen, they don't have to be in the same screen.
Being able to share the clipboard, could be done through UAE. Pass the emulated clipboard contents to the AROS clipboard and vice versa.
Being able to communicate via ARexx (if UAE could present dummy ports) - Does AROS have ARexx?
Being able to double-click to run games. That is have a file (either a configuration file or perhaps a package of diskimages+configuration ala OSX bundles) that can be launceh from Wanderer. This would be so cool, it would have an appeal to the Retro crowd.
More of an enhanced UAE than a change in AROS.