My copy of P4 came with P2 characters so I have no reason to believe that backwards compatibility will be forgotten in P5. I strongly suspect that we'll be able to use our old favorites - and even new ones that appear between now and the P5 release. As an example, although Mike and Vicky are available, I (and many others best I can tell) still use Posette and Dork. Obsolecence (is that a real word?) is somewhat relative. Keep making stuff - at the very least it's good practive!

Before they made me they broke the mold!
http://home.roadrunner.com/~kflach/