They're probably going to do what they did with FR/LG, make you wait until you get a National Dex of some sort (which frustrated me, I was flipping out trying to get a Crobat until I read that you have to defeat the Elite Four first and BLAH BLAH BLAH). Anyway, most of the new evolutions in D/P/Pt were pretty fail, anyway, (with the new branch evolutions being exceptions, they were pretty awesome.)
But what're they going to do with Pokemon like Magneton and Nosepass? Don't they evolve in Mt. Coronet?