Unfortunately I think you're right that Scala is too complex to displace Java. If you're looking for a functional language you can use to to real work though, Scala is just the ticket and it's really not that complex once you start using it. None of the above-average programmers I've worked with would have any trouble picking it up with a little motivation.

Personally I find myself much more productive in Scala for anything non-trivial than in any other language.