I think after playing Castlevania: The Adventure Rebirth, I'm all for remakes in the sense that they're full reworkings of the weaker titles in the franchise. So for me, that means Simon's Quest, Harmony of Dissonance, and Portrait of Ruin would be perfect contenders.
And out of all of them, SQ has age as a major factor for it's lackluster quality, so I'm all for a fully unique countryside to visit with a more fleshed out game world.