Conquest of the Horde

I think that it would make sense for Tauren Druids to be allowed into Teldrassil even if no one else is. I mean logically the two races get along amazingly after all.
Also Undercity is locked to all non-undead, I think Blood Elves should be allowed in. The two races after all are extremely close. Again this is only my opinion, please consider it and make your own judgement call.

There are server-specific reasons that races can't visit said cities. Look on the wiki for the storylines and read up on a posted guide (was there one? I think it exists) on the forums. Essentially you can find out why people aren't allowed in without a discussion thread.