Polymorphic methods in enums

Yeah, this is the big difference, as each case in an enum in Swift is part of the same value type.

Yeah, I think you would need to have the compiler effectively synthesize the switch statement, else you need to emulate (or add a new language type for) the Java-style reference type enums.

Chances are you would not want to use extension for this, as other conditional conformances/method additions won't work.