Most of your points only apply to Scala.
Is there anything Play 2 Java can do that Play 1 Java + Japid template cannot do as well?
Seems like the move to Play 2 and Scala is more political than technical. The Play people formed an alliance with Typesafe, a Scala company, and thus decided to move away from Java and focus on Scala, abandoning their huge Java user base of Play 1.