Neal Gafter, another influential Java stalwart, has been a fan of Scala for quite a while:

"Will Scala be the next great language? Only time will tell. Martin Odersky and his team certainly have the taste and skill for the job. One thing is sure: Scala sets a new standard against which future languages will be measured."

I think that's pretty bullish. I would agree it will become more important, but surpassing Java? That is a very long way off if in fact it would ever happen. A lot of the Java world is very skeptical of Scala.

I think Scala appeals more to people who have background with functional languages (or languages with functional features such as Ruby) who want the performance and capability of the JVM without Java.