I think it's a great idea personally. The half-orc has limped around as a core race for a bit now, but only caught on with a small portion of the players... And I kinda dig a non-level-adjusted (as I assume it will be) Tiefling, perhaps Aasamir too?
I'll be interested to see the take on a race that's usually labelled evil and chaotic due to its birth, but then again, that never really affected half-orcs.
Heck, I'm still hoping for Kobolds to be a a core race (rather than say goblins). The 3rd edition Kobold seems overall kinda popular with the fans, so that might be nice to see.
As it stands, the only thing that I don't want to see is the 'fantasy standards' being the be-all and end-all race options... Some players (particularly in my group) like to go for exotic characters, and this means an immediate headache if savage species is pulled off the shelf. Tiefs. as a core race sounds good to me.