In my opinion, Yamane needed a break after Order of Ecclesia. I like the music but I never felt it was up to her previous standards, except maybe 3 excellent tracks. Also, listening to her latest work on the Skullgirls soundtrack, I am not really feeling it anymore. Again, it has maybe 2 great tracks but the rest is pretty forgettable IMO.
I do want her to make more Castlevania music, but I'd also like to see someone completely new have a go at it. I was very impressed by Jake Kauffman and his castlevaniaesque work on Bloodrayne Betrayal, but I've said that millions of times already.
But yeah, Yamane and Oscar would make an interesting duo, possibly awesome!