Both types of gameplay have their place and should stay alive. It is shame that turn-based is dying right now (and in a way transitioning more to handhelds/smart phones/tablets)
Since FF X, the Final Fantasy brand just has not felt the same. FFXII, while a good game, just did not have that same feeling to it. With the loss of the Turn-based feel, FFXII and FFXIII seemed to have lost more to me. They seemed to have lost their FF soul. Dont get me wrong, I played both of them (even have the Plat in FFXIII) and really enjoyed them, they just were not the same to me.
This is not to say that Action RPGs do not have their place. Grandia, Star Ocean, Kingdom Hearts, Tales of + many others are awesome games. I love some of the series to death and hope they stay the same as they have been. Could you imagine a Grandia Turn-Based RPG? How about Tales of? It just wouldnt feel right.
I am liking everything I have seen so far on XV, except for the name. It should stay apart (same with the MMOs) as it will never feel like a Final Fantasty Mainline game. At least not to me.