Limited mid-air mechanics are more realistic. And don't say realism doesn't matter, because we wouldn't be having this discussion if anyone actually believed that. I always liked Castlevania over Mario because Castlevania was more realistic than Mario. Granted, I liked Mario over Metroid because in spite of Samus being so cool and her various blasters being so awesome, she had way too much mobility in air as opposed to Mario, who could move backwards but with limited mobility. And taking that further, I always had issues with jumping in Metroid (and Mega Man as well) because of the freer mid-air mechanics. Too often I'd over-jump a ledge and try to compensate for it on the descent, but then overcompensate and miss the ledge on the opposite side. This was more prevalent on Metroid than Mega Man, but I still made that mistake a lot in Mega Man. At least with Castlevania's limited mid-air mechanics, you could easily learn to gauge your jumps. You would eventually learn to tell at a glance at which moment to jump off one ledge toward another.
Now, from a developer's standpoint, Castlevania is too constricting. Mega Man and Metroid allowed for more developmental liberties. You didn't have to plan out jumps too carefully. Jumps 48 high and 16 over would be just fine because the player could jump straight up then move over while in mid-air. In Castlevania, a jump like that would either force the player to smack his face into the ledge or jump through the ledge and fall to his death, so jumps would have to be 32 high. Or something. I'm just making up numbers. Still, that's my only complaint with Castlevania's mechanics.