Hopefully Apple does include MacRuby pre-installed.

I just wrapped up a MacRuby app. MacRuby is a very cool system. However, if you are distributing the app, you either have to include all of MacRuby, or go through a complicated and error-prone process of excluding portions of the stdlib. This is a black art at the moment.

Even without most of the stdlib, the bundled app is much larger than the equivalent Cocoa app.

The larger app size could become a concern on machines like the Air with smaller SSDs. It also seems tasteless to have multiple apps each with their own MacRuby distro bundled up with the app. A pre-installed MacRuby would solve both of these problems. Then again, it would also make creating Mac apps almost too easy... how will I compete?