Perhaps the difference in our experience comes a bit from the fact that you jumped straight into mp2 after having been a fully powered up samus at the end of mp1, free to go wheneve or wherever. I could see how going from
that to a world that will kill you in seconds to be a bit off putting. It had been a year or two for me between them, and I've always expected to be restricted at the beginning of a Metroid game.
And come to think of it, the first area, agon wastes, is probably the least interesting level in the entire series. My fondest memories of mp2 do come from the latter half. The last level, the sanctuary fortress, is easily my favorite in the entire series. By the time you get to that point, the dark world has long ceased to do you any damage.
ah well, I guess to each their own, it just seems hard for me to believe anyone who loved the 1st and 3rd could so hate the 2nd.