Isn't the lack of GC on the iPhone's Obj-C runtime a much bigger hurdle than 3.3.1?
Exactly what I was thinking. I'd love to do some small things on iPhone, but I don't really want to commit the time to become pro at Objective-C. It's not a bad language, just not my thing.
If you've used C or Java before, you can become "pro enough" in ObjC in a matter of hours, maybe even 1 hour. The real work of designing an iOS app is getting the interface right, and any complex logic you might have. Nothing esoteric about day-to-day expressing yourself in ObjC -- plus Cocoa provides so many nice features that the verbosity you may gain coming from Ruby is offset by the amount of coding Apple took care of for you.
Yeah, it's really Cocoa you have to learn, not ObjC.
Very unlikely, I'd imagine, just from a performance standpoint.