The old materia system was kind of like what you want, no caps on stats, but the type of materia was limited by the piece of gear it went in, and sure enough, if you didn't have a hat at least triple melded with int, you couldn't get in a Garuda party, the stat allocation system lets you put points anywhere, but I have yet to see a bard with all 30 points in piety to maximize song durations. No matter the system, people will figure out what is best, and that will be what is expected. You would be able to try different builds, but unless it is endgame content, something like determination over crit won't really matter, it has and always will come down to endgame, and unless you have a group already, good luck getting one when you and they both know you aren't gearing your character in the way that most benefits the group.