I think I read your post wrong. Anyway, to circle back a bit, I'll conclude that I never thought the gameplay was bad in the series. However, I do find the narrative aspects extremely problematic. I know, I know, a real gamer would just skip over them and call it a day to get back to the real substance of the gameplay, but cutscenes and codec conversations clearly are a heavy, heavy focus of the series. My utter disdain for the series' lore at this point is a big negative. I never did finish 4 just because I was that annoyed by the endless interruptions to gameplay (the fact that I often don't finish games these days probably factors in as well).
Like I said, I'll probably check out Ground Zeroes at some point just to see what new bells and whistles were thrown into the Fox Engine. But, any enthusiasm I had for the series has long since dissipated. Ground Zeroes is probably in "I'll pick it up for $10" territory.