We just had a discussion similar to this in my gaming group. One player is under the assumption that more is always better, I on the other hand think there are really only a few things that the game needs.
1. a malicious expantion, make it PoD or 60-75 bucks if you need to, I don't care. Everyone wants to play as the bad guys once in a while, so throwing in the bad guys would make the some ruples. Dark elf, Skaven, human Chaos followers, and orcs and goblins. Call it winds of chaos, or realm of chaos, rise of darkness, whatever. Bam, deposit money now.
2. an elf based supplement, dwarfs got theirs, some or the content is even really enjoyable. silver helms, glade guard, eternal guard, dragon princes. whatever else tickels their pickel
3. humans other than empire that can help the empire. the biggest of these : Brettonia. I love my knights of the grail supplement for 2'cd edition and it didn't take too much to convert those careers to something useable for 3'rd, but I would love an official supplements. These can easily be PoD, there no that different from empire. careers to include : peasant throwback cannon fodder # 1,2, and 3; knights errant and questing knight definately, if you're in brettonia as a setting, knights of the realm and grail knights; robin hood shooty career 1 and 2, shepherd career; throw in some fancy pants tiliean mercenary career or two, an estalian merchant career, and maybe even a cathayan fairy career, er samurai or ninja or something I meant. Make the border princes a campaign setting and easy justification there.
4. advanced careers for non human, easy PoD fix in my opinion. 1 or 2 dwarf, 10 elf waywatcher should have been an advanced career in my opinion, and much beefier than it is.