Question on Npc relations

[Niwashi]

is this something that they are stepping away from in their games in general.

No, I think it's just this one. In most of their single player games, SE designs the characters, complete with backstories and interrelationships. The characters are part of the story. Here, as an MMO, we're given a story, but we design our characters ourselves. While the story places a few constraints on how we can roleplay them if we want consistency with that story (no good/evil choices, for instance), we're still given a lot of latitude in what personalities we want our characters to have.

Some players play their characters as representations of themselves. Some roleplay and come up with their own character stories. SE themselves tries to stay noncommittal about what their personalities are in order to give us a wider range of choices in the matter. They basically tell us that our character is interested enough in helping Eorzea that we'll attempt all the stuff that goes on in the main story. And they tell us that our character is at least willing to work with a number of the NPCs that SE designed. Beyond that, though, how our character feels about any of them is largely up to us.

Like will it be missing in 15 as well , from previews Ive seen it looks like there want be any in that game either.

Noctis is engaged to Lunafreya. And judging by the Brotherhood anime, I think Prompto has a bit of a crush on her as well.
She didn't appear in the Duscae demo, but the road trip they're on was supposed to be for Noctis to meet up with Luna to get married. (Then, while they were on the way, his country got overthrown, so they've got other concerns and it's a bit up in the air as to what's going to happen with the wedding plans.)