I would very much love Final Fantasy V to be remade in 3D! Just imagine all those outfits from different classes from EACH characters! But if they do that, it'll be very much compared to Bravely Default, since that game utilizes the job system. Though the job system originated from FFIII, and FFV greatly expanded it.
So I'd say, if FF Tactics won't come to smartphones, I will surely hope for FFV 3D remake.
Whereas for FFVI, if it's going to be remade, I won't like it if the game gets the same treatment with FFIII & FFIV. The experience that I got with the 64-bit game back in the days were priceless. And without the Sakaguchi x Kitase team-up, I'll just want it for what it was. The FFVI has strong plot, that the game should be fully realized, like FFXV, so the emotions, fights, and confrontations can be correctly conveyed. But like what I said earlier, without Sakaguchi, even if it's just a remake, it'll be totally different. My favorite moments might turn out to be a forgettable one if not executed correctly.
Sandy boots.
FFV 3D Remake: Yes
FFVI 3D Remake: No