This is a tough subject, and I'd like to state up front I have 0 influence on price point.
Nevertheless here is my take on it: "Entitlement"? just because a game is not different from what you already purchased on "platform A" does not "entitle" you to get the game for free on every platform, or even one additional platform. You bought the game for Vita, so you got the game for Vita. Done deal. That entitles you just as much to the PS4 version of the game as to the PS3, Xbox360, Xbox One, iOS, PC and Mac versions of the game: it doesn't. Would I *personally* have considered allowing existing players to get it at a reduced rate...probably yes...but that is not my call to make.
Regardless of my personal feelings towards rewarding the playerbase for their business and loyalty, there is no entitlement. period. You are also not entitled to get free games or even free updates, the free updates are a service Re-Logic gives to their players to thank them and keep them interested in the game. There is no entitlement, ever. You paid money for a product, you received the product. That ends it. Buying The Avengers on DVD does not mean you get the Blu Ray for free...unless you bought the Blu Ray pack that has a DVD and a digital copy, but guess what...that one is more expensive.
As far as the PS4 version goes, it costs money to port a game to a new platform. Any. new. platform. It is not like we just took the PS3 game and put it on a PS4 and that magically works. 505 Games (the publisher) has invested (quite a lot of) money into developing the versions for the newer consoles, testing those, translating those, marketing those and pay all due fees for age ratings and platform holders. It is their perogative as a commercial business to charge people for purchasing it, since it actually is a *new* product.
So, long story short: entitled: no, would it have been nice: yes
/discuss