and on the horde alongside the Blood elves as the allies they were under Illidan in TFT. Things could have been different if they didn't stick to rules like each faction must get a new race or only 2 factions.
Looking at Macaree, the horde would have been awesome with both the Draenei and Blood elves on it and in fact the story fits better with them as friends - two highy intelligent races, one naturally magically adepts the other technomagically advanced- sharing the light connection too, and both races being raped by the legion's actions and betrayal by their leaders (Queen Azshara and Kil'jaeden/Archimonde)
I also think it would have been nice for the horde to have another non-elf advanced civilization, and tbh I think the Eredar Draenei fit the horde look feel better, and with the blood elves with them I think that would have been great balance.
Also do you think it wold have worked out better if they gave the alliance high elves too while the horde got blood elves and draenei? Personally I think the alliance would have been fine without any new race in TBC, and in another world maybe both goblins and elves would have been shared.