I'm here to see what happened to an old friend.
If open source re-ignited interest in the desktop then yes I might come back, I don't think it will though. I believe the aim of open source is to boost embedded applications - so if I'm looking for a platform to implement my toast making algorithm on, I might now pick RISC OS.
Would I contribute? Had the open source appeared five years ago then I would have done. Today I'm not in touch with what needs doing.
I have quite a lot on my plate as it is.
Never say never, but I can't see an immediate return to RISC OS.
I would be open to contributing existing source code - if there was anything useful, thinking components or bits of code here not applications.