You can go back and forth on the quality of the VA, but the one constant is that the writing is mostly awful. I've never considered Kojima a particularly skilled writer in that regard. I think he's a guy who has remarkable, interesting ideas, but hasn't the skill to distil that into really compelling dialogue. The guy just needs to feed his idea to a skilled writer. The series hasn't moved on much since MGS in terms of writing. I've also never been sure just how intentional the really camp moments in the series are. Is the blatant homoeroticism of the series intentional or a by-product of a blissfully unaware individual? I don't know, but it makes for a really unusual juxtaposition to have these high camp elements mixed with these uber serious moments. Tonally, it's the strangest mainstream game you'll ever play, it's all over the place and that's great in its own way. I just wonder how much of it is intentional.
What I find odd is the rare moments of subtlety he overwrites in subsequent games. I thought the explanation of Liquid possessing Ocelot was more interesting when it was a supernatural by-product of him being The Sorrow's son. Then there's Vamp, who, if you pay close enough attention, seems to be healed by water in some way in MGS2. A far cry from the catch all deus ex machina of nanomachines in MGS4. Kojima embraces the supernatural elements of the series in one sense, only for him to quickly abandon them when faced with how to explain them. In a way, post MGS2, it's a series defined by vocal, negative fan reaction. It's had a profound effect on Kojima and his approach to the series, I feel.