Unless we hear something from Falcom about that soon, it's not going to happen. They honestly need to get the PS4 version out and move on to other games, not worry about back porting features to Vita, when the Vita version has sold about as much as it's going to sell in Japan. We're already looking at what will most likely be a summer 2017 release for Cold Steel 3 in Japan (if it even comes next year). The more time they waste on older versions of games, the less chance of us seeing certain versions of the game over here when we get it later in 2018.
That is a good point; we have no idea how graphically intensive the new content is in the PS4 port.
Either way, glad the game is coming over and just was shooting an idea I had, considering I've been playing Grand Kingdom the past few weeks .