I think you need to put the battle systems into the context of the time these titles were released.
When Chrono Trigger released, it was essentially an evolution of the ATB battle system (this is all from memory so correct me if I'm wrong). It had a few cool innovations like the Combo Techs that for the time, built on a solid foundation. This battle system would go on to feature in the next three PS1 Final Fantasy titles, with a more strategic variation/evolution in FFX.
With FFXIII, the battle system was born out of a necessity for the jRPG genre to innovate/modernise beyond the ATB system (which was over 15 years old by this point). Whilst half-hearted attempts were made by SE in the previous gen with FFX and FFXII, they didn't establish themselves in the way ATB did.
The fast-paced battle system of XIII, whilst fun, is designed to remove the player from the action and put them into the role of an overhead commander; letting the AI choose the best course of action and simply changing formations at the right time. Most players can't do manual input due to the fast paced nature, so it becomes a case of timing the formations mixed with the pot luck of having the AI characters choose the appropriate places to stand; you have no influence on where character position themselves which is a pain for attacks with large areas of effect.
I don't see the FFXIII battle system progressing much further in the genre next-gen like the ATB system did for all those years. Personally, I would have preferred an evolution of the FFXII battle system in the way Xenoblade did or an outright action system like FFXV looks like it will do.








