Yeah, that's probably where the 'too much plot' thing comes from, which is somthing I agree with, even as a fan of the series.
I enjoy the series (hell, I completed MGS in one sitting) but it's the storytelling which is great, while the plot itself, post MGS1, leaves kind of a bad taste in my mouth. It's like the anti-halo (a series with some of the worst sorytelling in the history of games, which is a pity since the plot itself is actually quite good).
All opinion, obviously, but it says a lot that even Kojima regrets making the plot of MGS2 so complex (which knocked on to 4 so that loose ends could be tied up).