I wonder if the reason so many people didn't like TSR's metaplots was because such things weren't part of D&D, originally.
From what I understand, OD&D, BD&D, and AD&D 1E didn't have metaplots in any regard - just stand-alone adventures and the occasional sourcebook on a static setting. If you wanted to drive a campaign forward, that was completely reliant on you, the DM, to come up with. Pre-made dungeons were essentially there to be used as you saw fit.
By contrast, Second Edition - perhaps in response to the rise of other RPG companies that reveled in metaplots - had metaplots for most of its campaign settings (which themselves suddenly started to proliferate), something which I suspect was jarring to a lot of long-time players, and probably was the reason a lot of old-school fans left when 2E came out. Suddenly the world you were organically growing around your campaign was being dictated to you, so it's natural that quite a few people didn't care for it.
If that was the case, then it's less a question of having a metaplot or not, since there are clearly people who like them and others who don't, but rather is an object lesson in not suddenly changing the style of the game.