If the Main Quest gets extended further by, say the release of a disk based large scale expansion pack, do you prefer:

Something like XI where Main Quests between expansions are independent. Completing the Main Quest from one expansion pack is not necessary for starting the Main Quest of another expansion.

OR

Make everything canon and continuous. Everyone must complete the vanilla Main Quest in order to play the expansion Main Quest(s).

Personally I prefer the latter, this way it makes much more sense story wise and feels more involved in the world.
However I am well aware the fact that it will be a deterrence to new players who join late and may just have too much catch up to do. But the former can easily cause things like plot holes or unrealistic experiences, which to more serious gamers it just feels awkward.


What are you guys' opinions on this?