[UnchainedAcolyte]

City building with the opportunity to have transportation to/from the cities, bonuses to certain skills, and mayoral elections. (SWG)

The ability to own something other than houses or a guild hall, like a cantina, medical facility, etc. and the ability to boot people from your establishment after entering if you so chose. (SWG)

Viable non-combat, social professions/skills that didn't have a combat skill/level requirement (medic/dancer). (SWG)

The ability to play a non-humanoid race like dragons (Horizons).

The ability to multi-class/hybrid-class/trim classes back in a level-based environment, balancing multi-class benefits with slower leveling (Horizons).