Any ideas for a satisfying system to hit a lot of the notes of the Saga jrpgs?

>Classless, and levelless, characters advance by using abilities (more sword attacks mean eventually getting big flashy sword moves, casting more gets you more mp and the like)
>Martials get some cool options that range from parrying, to big flashy grapples or typical flashy swordsman stuff
>Anyone can choose to suddenly invest in a weapon or magic even though they'd be set back for a while versus someone who dedicated earlier
>sort of grounded for a jrpg for the most part but you do get into big fights with wild forces of nature and big powerful evil

With my own due diligence I noted Sword World, BRP/Mythras, or Fabula Ultima. I'd like some more siggestions if there's something more obvious I may have missed. Fabula Ultima is cool but that's more FF and doesn't quite work. While Sword world is level and class based, you can freely level any new classes to become more versatile which is pretty close. Any input or opinions are appreciated.