I didn't expect to feel optimistic for this show, and even now I'm kind of scared to. When it was first announced, my friend and I were pretty certain they'd end up doing some throwaway CG bit, but stubbornly we still wished for something that resembled Vampire Hunter D. Surprisingly, from the teaser, that actually looks a lot like their inspiration here. I don't know how they managed to get through Konami's nonsense in order to pull this off, but now I'm feeling like it's possible that someone in charge of this thing might actually give a damn about Castlevania.
Speaking of Warren Ellis, the guy's done good character driven stories for a bunch of properties (lot of Marvel stuff, my personal favorite was his work on Nextwave), so with CV3 as the framework, and enough creative freedom, he's definitely capable. If he's invoking his experience from a series like Hellblazer, then a project like this should be relatively straightforward for him as long as plays it well with the storyboards.
Of course, that also depends on what animation studios are working on it. Is it true that what we've seen so far is all from Frederator? That might actually be the bigger surprise from all of this!