I doubt if you can wait. Sun has only recently finished gathering the people required to start work on the questions. I think it should be another year atleast before they are out with the exam.
As for the part about J2EE Vs J2EE5, I would agree that waiting for the next SCEA might expose you to a few topics more like EJB3. However SCEA part 2 - the assignment would still be as challenging as it is today. You are free to use any J2EE technology for part II and you should wait only if you feel taking a different part I exam is worth it.