Bejeweled 3 would be amazing to see.
Tetris would be nice, with REAL trophies and more game modes and not just the Mini's, sadly EA would probably screw it up somehow.
A Sim City like game would do the Vita really well.
Amazon Instant Video would be a good addition.
Pandora would be nice but I'm sure it will never be included because they want people using Music Unlimited.
A slot machine game with the concept of The Pinball Arcade(Adding slot machines in with DLC)
A River City Ransom clone would be badass too, or a remake of Rampage.
Sony also has to figure that people readily have smartphones, a lot of people have tablets, how many people would double dip certain games to be able to play them on the Vita? That is probably why a lot of games aren't included(But, it also takes time to develop said games.
The real question that comes to mind....you have a lot of great ideas, why can't someone in the Playstation Mobile Development system, replicate said game? You now have the potential to. This is why Playstation Suite is in open beta, they probably have their hands full, churning out several games for PS3, and a couple for the Vita.
That's exactly why they haven't made any, no one would buy a Vita for the "pick up and play" games only, they buy them for the hardcore, in-depth games. People who play games like that would rather buy a multipurpose device like an iTouch or Tablet to play those games, as well as having the added bonus of an actually competent storage system, Music Player, video player, HD screen, fully featured web browser.
And for the replicating of said games, you can't just copy them (or else you'd face lots of copyright issues). The original makers would have to make a Vita version. And they're probably busy making money off their next big games on smartphones.
It wouldn't be a sure in sell to get the Vita but it would be a nice edition to the Vita. I'm not saying that all of the Vitas games should be made as small little games from now on but they'd be a nice addition. And I never said that they should straight up copy them from the iPhone.
I still think adding in little games like this would be a fun idea. Not to mention that they could be redone in amazing Vita HD and maybe a few PSVita features added in. I feel like JetPack Joyride made a good place in the Vita.
I honestly want Fruit Ninja the most out of all of the titles I've suggested. It was great on the iPhone, kinda of cool on facebook, and amazing as an arcade machine (Dave and Busters).
I'll also update the thread a little bit to put titles you guys suggested. I haven't heard of Cave Stories but I'll check it out.