OK, first off I will start by saying blizzard can and does do what they feel they need to. Blood elf druids can be found in the game( links will come later as I am tired and wanna finish this thread.
I did however find this on wow-wiki "High elven and blood elven druids"
Main article: elven druid
High elves have also practiced druidism; they had elven druid. The Elven Rangers have practiced it, too. It is also assumed that blood elves have also been trained in the art of the druid.
OK so now comes Undead Paladin: easy enough Mor'ladim in raven hill hes a level 30 elite and hes undead(scourge) and hes plainly a paladin. I don't care either way I am just saying from blizzard perspective it is possible. so with that much evidence Discuss and I'll add the links tomorrow. But feel free to discuss please no flamers or whiners) serious conversation about the game and its future.