For me, it's Portrait of Ruin. Such a fun game. You got a lot of weapons and spells, and the team mechanic was cool. Plus, it has the most bonus modes out of any Castlevania games, and all of them bring something interesting with them, which I also thought was great. Oh, and the music is an eargasm.
Dawn of Sorrow takes second place cause of Julius mode, then it's a tie between SotN and Aria.
Also, I don't think Order of Ecclesia truly qualifies as a Metroidvania.
It removes one major factor that all the other games have, which is non-linearity. In OoE, you have levels that are given to you and that you have to complete in order to unlock new ones. Only about a third (if that) of the game is taking place in Dracula's castle.
Also, the best idea ever to obviously take from PoR is making re-colored versions of the same level. Also, fuck bosses with autoscrolling. Oh, and the healer guy is an asshole.
It's a weird hybrid between Metroidvania and Classicvania, without being truly successful at it. Although I have to give it that its difficulty was just right.
For the same reason, I would remove Harmony of Despair, which is no Metroidvania in the slightest. It has set levels that you complete, no real exploration. You only carry over powerups. It also is like crack. It's bad, but you can't help but play it.
and the combat was faster than the other games
No way, lol.
"HI IM SHANOA IM GONNA SLASH 3 TIMES AND THEN I GOTTA STAND AROUND FOR 5 MINUTES TO RECHARGE MY MANA KTHX"