You might have expected one. After all, Castlevania's been represented on almost every handheld that meant anything.
It's also a name that tends to sell well.
When Mirror of Fate HD was announced, I'd though that finally the Vita would be recognized, but it never happened (and to hear Eric Alvarez talk about it, a Vita version was briefly mentioned in a developer's meeting, but never seriously considered).
I'd enjoyed Dracula X Chronicles and the refined SOTN port on PSP tremendously (I actually wore out the UMD!), but was always slightly disappointed that it was a remake and rerelease, and not new content. I'd hoped for a Castleroid or even a 3D Castlevania on Vita, given what the hardware was capable of, but Konami, like almost every other company, kept their distance from the system save for some animesque low-risk-low-reward games and then used the resulting low sales as justification to completely abandon the system altogether. Konami doesn't get sole blame for this (everyone, after all, was guilty of this almost from the outset), but it is so appropriately them to do so.
Seriously, the Vita's ability to do a decent 3D Castlevania (albeit a linear one like Lords of Shadow) cannot possibly be understated. The analog sticks and touchscreen would have made for a great combination (like dragging your finger across the touchscreen, or even the back panel to flail the whip defensively instead of holding the attack button and waggling the directional inputs as in older games). The graphics would have likely been impressive for a handheld, and one could easily expect it to control responsively beyond what could be done on the DS or PSP.
In the end, I doubt we'll ever find out what potentially awesome Castlevania adventures (or adventures of any sort) that might have been on the Vita; especially given that it seems like Sony was conspiring to murder their own system since day one, and game developers seemed only too happy to help them.