Now that everyone is talking about the final days of the Vita since a lot of services won't be available anymore on that system I was thinking whether this could be a great opportunity for the PS4. 

The Vita didn't spawn the worst games, no, it actually had some enjoyable and even some great games available. Most of the indies are becoming available on the PS4 system but there is some potential hidden with the handheld AAA games that should, in my opinion, get a transfer to the PS4.

Killzone Mercenary HD: 

Since the game is built with the same engine as KZ3 there and already running on a VITA porting the game over on PS4 shouldn't be seen as a difficult task for the devs while using the original sized textures, outputting it on 1080p and adding some of ShadowFall effects. The game is one of the best in the franchise and by leaving the SP intact and maybe increase the MP a bit (6v6 for example) this could become a great seller (cheaper price obviously)

Soul Sacrifice 2 and Soul Sacrifice Delta HD

Releasing Soul Sacrifice Delta on console so that a lot of people can play one of my favorite games that has been released on the handheld for a cheap price online (12 pounds - 15 euro - 18 dollar) so that people are familiar with the game before the sequel comes. Such type of game would do well I guess in Asia but there is also a market in the West for these kind of games.

Gravity Rush 2 and Gravity Rush HD

Already announced but we haven't heard anything of it yet and rumours were spreading about it to be a PS4 game currently which would't be surprising. With Cell shade graphics an enhanced version shouldn't be that difficult. And the only real touch screen elements were sliding and using the skill tree. Easily to be assigned to the PS4 touchpad/extra triggers. Same price as 

Freedom Wars HD

Don't know how but Japan Studio is really making great games for the Vita each year and now that The Last Guardian is out of Limbo they should really bring more games to consoles. The above two or example but maybe Freedom Wars is the number one contender for a remake as it is their fastest selling Vita game. But it could have something to do with game drought. Still, even if they release only one remake out of these three t would be okay. Freedom Wars would definitely be better on PS4 because of it's online capabilities and social play.

I think these 4 games should get the console/PS4 treatment next. Especially since Tearaway will get a reimagining while Toukiden and God Eater 2 get a remake on PS4.

Which game do you want to see on PS4?

The three bestselling Killzones. The PS4 Killzone has only been out for a little more than a year. It's got a decent shot at becoming the bestselling in the series.

Aren't you people overreacting a bit about the lost of a Map application that was only useful on the 3G model that was discontinued 1 year ago and few people had and the YT app?

It's not like they didn't released Resogun in December and paid for the Grim Fandango port. And we still have the games confirmed in TGS for 2015.

Edit: Oh, and Sony's own MLB15 game too.

a vita game ported to ps4 would "look like shit" based on expectations.

i'm happy more people will get to play tearaway but MM is giving that port a lot of love. killzone would be a big let down and not worth it. same with soul sacrifice and freedom wars.

i do hope that gravity rush 2 is taking so long because it is being redone for ps4 and that gravity rush one gets a quick port (pre-order bonus?).  that game was great but even as i played it i thought this would be better on a full console.  as a sandbox game on handheld you could really feel the low enemy count and world detail downgrade in order to make it work.  i would love to see this series move to ps4.

Yeah, people are... They just added the PS Live app not long ago, they wouldn't have bothered doing that if the removal of these apps meant what people are thinking it means.

I don't think we can always use the "game X on the same genre sells Y every time". So all racing games are flops because GT sells 10M and all sandbox games that don't make the GTA's 30 to 40M sales are massive fails.

Yup, I agree, everyone mainline Halo has sold pretty bad. I mean, since the franchise was born, it's only on average sold ~4 million every year, and as you say, that's not remotely close to CoD.

That was a cheap shot and you know it

Yes, it's not like they aren't doing actual games for it. But it seems everyone used it for YouTube, maybe people don't have smartphones or tablets anymore.

I think it would be better to just have those teams assist with the AAAs and speed up the process a little bit.

Gravity rush 2: pretty much garunteed a ps4 release.
Killzone mercenary: Could see it being released with the two psp games in a collection.
Soul sacrifice/Freedom wars: Hunting games sell better on handhelds and to be honest fit better on handhelds. Not only that they sell the most in japan, handheld region. I can see sony putting it's resources towards something that would sell better.