It's more about the fact that elite D doesn't help too much. I know Bergman (not that i think he's AS worthy) and C-Costa have lvl 17 D or higher and that helps them limit opponents pretty well but i think that doesn't do much to help selection. It's more about what you score/assist etc as opposed to what you stop opponents from doing.
As for what sort of D i like....the more there merrier. Tremendous is acceptable for starters on my team but i'm hoping that i can get all my starters to Marvelous or higher at some point in the next 5 seasons......big dreams i know!