I'd like to think that there's a bit more to my options then "virtually no plot" and "best intertwining plot ever", just like there's a fair bit more of a spectrum to games than "drama-driven RPG story" and "totally plotless fighting game". In this case I view it as a sliding scale, where the better the gameplay is the less strong the plot can be (though of course the best games are almost always good on both), as long as the addition of the two clears a certain mark. I mean if you look at it something like 80% of RPG's have virtually identical plots (Bad Guy breaks into the kingdom and steals princess/McGuffin, home town gets wiped off the face of the earth, travel around the country collecting your McGuffins to beat the bad guy, beat up the bad guy) but that doesn't mean I can't enjoy it.
I guess what I'm saying is that I'd still be perfectly okay with a game being lackluster in one area (such as taking a B-rate plot or character seriously) as long as it is good enough in other areas to make up for it and it doesn't dip below the "this is absolute shit" threshold. Nor do I see the only options being "make a good plot" or "don't have a plot". I mean even bad plots can sometimes have good moments, and I know that I certainly enjoy games that make at least an attempt at having a bit of story (even if it's not the best one) much more than simple "fight this, then fight that, then fight the boss, yay you won" games.