first of all, im using my laptop, no arabic letters and its a mac, so even if i can type in arabic, the locations of each number is kinda diff -_-, so plz bear with me :P
i DID play warcraft 3, read as much as possible about he lore, read for hourse about the lore in wowwiki, one of the reasons i play wow tell now is the story ^^
it might be possible to turn them into 3 faction in the story as the alliance in general have a bit weak bonds, and the forsaken are using the horde, yet helping them too, but when it comes to the game, its impossible to make 3 factions, that would mean a whole remaking to the world of azeroth from scratchs.
i still think that humans and elves dont work good together, humans in the story are kinda annoying and dont like any other races. the way they treat other races in wc3 is most appearant.
goat like? u mean the satyr? or children of cenarion?
goblins as a faction is gonna be really harde, as they are mostly nuetral and they wish for war and stuff to profit from it, they are traders and weapmon makers. they dont have much loyalty to alliance or horde, but they did help form time to time, they dont want the alliance and horde to stop fighting, but they dont wanna be doomed by other forces :P
under sea/maelstorm etc, it has many names, it is gonna be mostly an expansion about azshara (if u dont know her u have a lot of reading to do ><), she might be stronger than the lich king himself (and i mean the new one, the merging of the lich king and arthas), no one is sure if its gonna be under the water (low part of azeroth) or some other content thats above land.