I would argue that "too much" content isn't the issue, it is "too much of the same" content that is the problem.
Kingdoms of Amalur, great example btw, is a tremendous game and some of the questlines, the warrior guild questline for instance, have both clever little set pieces, tracking the merchant caravans and gathering clues, as well as story arcs that relate to the wider world. Those are fine and I would say you can never have enough of quality stuff like that.
KoA also has a metric fuckton of "deliver a letter to A", which is purely there to introduce the player to new areas and should be handled by the 'quality' content, and the good old "kill 10 wolves and brang the pelts" bollocks.
Now I would argue that GTA 5 does not do this. It has the whole "strangers and freaks" side-quest system which I would regard as quality and distinct content and not dross.
Skyrim is... I dunno, I think I'm going to have to be a tad hippoctritical here and say that I really enjoyed all the bloat. The fact I could roll up almost anywhere and be given loads of stuff to do was something I found really positive when I started playing. I guess now it is a little bit like porn you've seen loads of times before? You know what's happening next so you just put it on fast forward.