Main things I want out of Scala:
2. No checked exceptions.
Main things that scare about Scala:
1. Bloat. One safe-looking line can generate a 30K class file. Helps explain how their own jars are so big.
2. Slow compiler. That they need an 'fsc' ('Fast Scala Compiler') sort of scares me.
3. Creative operator overloading (':::', '/:', '|-', binary '!', and so on since the possibilities are mostly endless).