funny that I had to come this far down to see an actual response to the OP.
in addition to these things you anticipate I also think some good stuff is on the way: Minecraft is awesome but I really think it needs top to bottom rewrite done by really good engineers who are more able to take advantage of the current hardware.
-better multithreading support
-much farther view distance
-vehicles/heavy machinery that can operate on more than one block at a time
-multiplayer game modes (CTF, rampart style battles etc)
-a marketplace where players can sell their creations to other players (similar to the steam workshop for TF2)