That wouldn't bother me in the least, for a few reasons:
- I don't consider a quest getting locked out on me to be a bad thing
- Choosing to blow off a guild, especially an important one, should always be an option, and come with an appropriate price
- Most of my characters have no intention of finishing the main quest or joining certain guilds, because doing so doesn't fit their role
- I would far rather have the ability to either fail or subvert quests than the false binary choice of 'do/don't do them'
- Quest-giving NPCs should never be exempted from the game's rules (i.e. do not make them 'essential' or ineligible to be a target for a radiant quest)
- I don't predicate my characters' roles on the ability to do a particular quest; as such, while I will seek out ones that are appropriate I don't necessarily have to do all of them on one character, so losing a couple isn't a big deal
I actually wish there were
more cases like Brand-Shei's, since then quest-givers would feel more like people than quest dispensers.
I am on a PC, in fact, and the first mod I made was one to remove the 'essential' and/or 'invulnerable' tags from everyone (except ghosts, who are supposed to be like that) who had them. While it doesn't fully reintegrate them into the game-world, they feel more like actual people when I can see a couple of them lying there dead after a Vampire or Dragon attack. If you haven't already, you might want to make/use such a mod yourself in addition to those two, since the ability to have them actually die fixes a lot of the problems by itself (can't be hassled by a dead quest giver, after all ).