Well, the only stat block we've seen has a devil as an "Immortal humanoid" instead of an outsider, but that's about it.
We do know there will be monster "roles" similar to the four PC roles, and possibly these will do some of the work subtypes do now. Certainly they will play a part in setting up the monster's statistical "chassis" (hp, Defences etc), though I wouldn't expect them to be something spells would respond to.
I liked this description from the moment I saw it. Medium is clearly the same as 3e; no change there. There are probably different kinds of Humanoids - (generic) Humanoids, Monstrous Humanoid, Immortal Humanoid, Aberrant Humanoid, Undead Humanoid.... Demons, devils, the various celestials, fey, and giants have probably all shifted to subtypes. Beast might be equivalent to Humanoid; Immortal Beast, Monstrous Beast. Plants, Constructs, and Elementals could make up a third base category, a more "object" oriented one.
Immortal Humanoid can't just replace Outsider, since many outsiders aren't humanoids (lantern archons, for one...and no, I have no idea how they might be qualified), but are probably still immortal.
3E Subtypes are one of the things I considered faulty the moment I saw it. Some Types are iffy (Giants for example), not well thought out at all, and it makes no sense whatsoever to tie Saves and Bab to Type.
The new system, which seems to be Size Metabolism Shape is one of the changes I'm most impressed by, because that is something I didn't think of at all. Though I acknowledge that we have yet to see if Shape actually does anything worthwhile.