Might seem complicated to do or just memory intensive, but I always thought Elder Scrolls should have given you more choices when coming upon a quest. Take those Daedra Quests in Skyrim for example. What if you didn't want to do them but instead once faced with them you could essentially... turn around and warn another faction and a whole different questline showed up to 'stopping' this certain Prince.

Or the main quests like Morrowind/Oblivion where we really weren't forced into a role that dictated our entire backstory(Example being, you can't exactly not do the main quest... everyone's still waiting for you to talk to the greybeards or what have you.)

I always thought a good idea would have been, show some other main hero NPC as the main pivotal hero of the game and every so often "gametime" you can choose to join him/her on it. If you don't, no big loss. . . he/she'll do it and be the victor while you're the leader of a thieves guild if that's what you spent your time doing.