The problem is, I just can't see how they can reconcile full-on action battle mechanics with a complete materia sub-system. I am more than willing to embrace change with this remake, but losing the awesome Materia system is just one aspect that I am not willing to accept, and I'm hoping that they've realised that they can't simply rip out such a core component as a full Materia system.
I'm hoping for some kind of middle ground here. The characters are all running around doing their own thing ala XV - whilst subject to the Materia combinations that you have allotted to them - with a queued command system for whichever character you switch to (which you can do instantly on the fly). So you can move around the field and opponents whilst blocking or doing a single attack, or, if you wait for your stamina to fill, you can execute a combo with your equipped commands: two physical attacks or a physical attack followed by a Materia, etc... making for some dazzling Advent Children style attacks and combination techniques, especially with your fellow allies adding their own assaults to the mix.
They could make it so that as you level up you gain more command slots (so 3 maximum commands, then 4, etc,...), and so in turn, you can execute more strings to your chains. Or they could even tie it into the weapon you have equipped, making you restricted to each weapon's attributes. Double growth Materia weapons can have both an 'unlinked slots' restriction as well as possessing less maximum combo chains, making you further consider their use in upcoming battles.
Imagine Cloud rushing towards an enemy, executing two quick swipes of the Buster Sword, followed by a Bolt spell and then blocking any possible counters. But with counter-mime equipped, he will automatically redo those last actions. And then while he is blocking that attack (or automatically initiating his counter attack), you can then decide to switch to Barret, and then to Aerith, executing Bolt spells which could then chain together to create an even more powerful Bolt effect with even more damage.
I don't know. Just daydreaming here.
Ultimately, as long as I can have a full Materia system somewhere in this 'evolution' then I will be happy.