They would make more sense than dragons. Dragons have no reason to be joining a faction and fighting alongside them/doing mundane quests, just like the SL races would have no reason to.
Drakonids/dragonsworn are mortals. From a lore standpoint it would be more logical to bend lore to explain why they're rejoining their previous factions.
DHs and DKs are part of the factions because they actually have reason to. Dragons have no logical reason to actually join the alliance/horde.
Plus why would a red dragon want to join the horde given their history & the fact that the Dragonmaw are still members of The Horde. Bronze dragons have timeways to protect/manage, no reason to join the alliance/horde.