Better races, lore, cities imho.
Horde bores me. I started as Horde and was sold on the whole ragtag group of misfits who gotta come together in a cruel world primarily. Only race I actually liked aesthetically was Tauren. I started in late WOTLK so after Cata released I decided to try worgen. After going through their starting zone I started questioning things, like “Wait… if Horde is trying to survive why did they attack the Gilneans who didn’t really do anything?” Then I learned about draenei, the Horde trying to “survive against a cruel world” and found they are the primary reason for the “cruelty” in the first place from my perspective. Went Alliance and honestly loved everything about them, and haven’t looked back since really. I love everything Alliance.