I think so too. MacRuby is perfect for Apple, as they control its implementation, and the syntax is far more approachable than Objective-C is. Also, no performance penalty when compiled, unless I'm mistaking.

Thinking on it, I'd only be slightly surprised (and extremely delighted) if native/official (as opposed to experimental) MacRuby support for Xcode and the new Mac App Store was announced at the next WWDC.