My point was that saying a game has stiff controls because of an 8-bit limitation is bullshit.
And yes, the game controls are stiff by choice. Just open your eyes to the way that the first game is designed: it's very obvious by the level designs and enemy move patterns that the controls are the way they are for a reason. Castlevania plays the way it does just as Contra plays the way it does; swap the controls in both games but keep everything else the same and you have broken games.
Your mention of Simon's Quest doesn't really have a place in this discussion because we're talking game controls. SQ is in many ways experimental, and I guess one could say flawed, though I personally adore it. Compared to the first game, yeah, the level designs are lazy, the strategy is missing, and the controls aren't custom-fit for the game, it just takes the way the first game controls and slaps it in bizarre levels. But again, we're talking controoooools, and it's obvious by the way that Castlevania I, III, and Rondo are designed that these controls are intentional.