First, I love the MSQ, some parts less, some parts more...but in general I love it, and I think it's a great feature that makes FF14 what it is.

That said the MSQ is a huge barrier to entry, although if my personal experience, the people I know who quit have done so for other reasons, although for a few the MSQ was the nail in the coffin. They might have stuck longer, but would have quit at some point for another reason. All the people I know who love the fundamental mechanics of the game have stayed with it even though they are not fans of the MSQ.

The issue is also having to do it all at once if you start late. If you play it as it comes out it is far easier to get through if you don't like that much.