I don't know if FFIV is popular enough to get a VII style reboot or a series. The After Years was OK but I don't think I'd play it again.

I think FFIV has gotten a lot of attention over the years with the Advance remake adding a challenge dungeon and the remaster on DS. I'm not sure there is much more they need to do with it. I'd much rather see a remaster of FFV or FFVI before IV.