Oh, I forgot to mention that Lothos and some of the other betas have helped out a lot with optimizing the production AI. It can build some really mean unit compositions now and is much harder to fight against.
Aye, there is a new way to design units via the LUA custom country files. You no longer have to make massive methods. You can design your own divisions in about 10 lines of code or less. The core LUA code will then handle the rest.