I would love to see quests that can't be done by every single type of character. It never made sense that a melee character could become the leader of the Mages' guild. Or that my mage could command the highest seat of honor in the Thieves' guild. I want guild specific quests to utilize the skills you would actually need in that guild- Mages' guild quests should involve magic, thieves' guild should involve sneak, lockpicking and pickpocketing, and there shouldn't be cheats around it! I would even like quests that require certain levels of skills.
I would also like to see this in the world because it encourages me to go back and play another character if I want to see every piece of content. I want replay value and this would offer it.
What do you think?
edit- class was a poor word choice. I mean skill, as in destruction, conjuration, lockpicking, etc. Sorry!