What I think should be done is .
For the trolls make diffrent sets, Ice troll, Forest troll, Dark troll and the Jungle Troll, Jungle troll.
The Ice troll would be more of the type of "orc" it will have raw power, but it will also focus on other atributes, the Jungle troll would be a agile race, focusing mostly on swiftness, the Dark Troll would be the race most would choose for a spell caster, it would focus more on intelligence, then the Forest Troll would be able to be like the "tauren" focuses all out on strength.
Then I suggest there should be the Naga race, from level 1 they should be able to swim like the druid's aquatic form, And as they gain levels they grow larger razor spines that could penetrate attacks.
Ogres, My suggestion for Ogres would be there would be the 2 diffrent types of Ogres, and if either had 1 head or 2 it wouldn't matter, the one ogre would be the Grim-Batol ogre, the ogre that would focus of demonic intelligence, and would be most likely blue, the Spellcaster type, then the Warrior Ogre which would be the normal ogre.
Pandarens, they should be able to gain more fighting strength in battle or spirit, to cast spells with more power , by drinking their beer.
Demon...If demons where made they wouldn't be able to start off with such Godlike powers, I would say if to add demons, they should start off a Imp, a small flying creature, but as they gain levels they gain physical appearance, Height, Weight, Muscular build, obviously there would be a peak level to this.
And I believe Blizzard left something out, I would think you should be able to engage in hostile actions when riding on a mount.