The Vita exclusive Assassin's Creed: Liberation scored 71:74% on Game Rankings illustrating that it was not the greatest hit of the Assassin's Creed franchise. It's predecessors (in the above order) scored 82.92, 90.01, 87.64 & 80.05% on the PS3 & Xbox 360.

The following article on Eurogamer talks about how AC: Liberation was created for the PS Vita: http://www.eurogamer.net/articles/digitalfoundry-assassins-creed-vs-playstation-vita
It implies that the challenges of creating a vita exclusive title can be easily dealt with if Ubisoft choose to create ports of the above mentioned games to the PS Vita.

UPDATE

In light of the recent announcement that all PS4 games are highly encouraged to by Sony be capable of Remote Play on the PS Vita, some of you may be wondering why a port is necessary.

Here are the words of Jon Evans of BackwardsCompatitble.co.uk from the article: http://www.backwardscompatible.co.uk/what-is-the-future-of-the-vita.html

"The remote play process renders the game footage as video and transmits it wirelessly to the Vita. Latency should not be an issue either as you are close to your console..."  See where I'm going with this?

He goes further on to say, "So far, though, my experience of remote play hasn’t been that good. I can use it in my home network, although having a three floor house means I get lag on the top floor. I have no success using it remotely from another network in another location. This may not be entirely Sony’s fault; with a range of routers and network speeds in homes and different setups from ISPs it’s a challenge to be consistent."

And that last paragraph is why I don't believe Remote Play is the answer.  If I have to add to that in my own words, "I bought my PS Vita for use on the go and when my full console experience isn't easily/readily accessible.  Why should I fiddle with attempting to get remote play to work, when I can get full experience titles a button press (and screen tap) away however far from my console I may be (be it metres or miles)?"

We thus call on Ubisoft Entertainment S.A. to create ports of the following to the Sony Playstation Vita:
- Assassin's Creed
- Assassin's Creed II
- Assassin's Creed: Brotherhood
- Assassin's Creed: Revelations
Or at least explain in detail why they choose NOT to perform the ports.