It's an ok idea. The people who write on the forums the most will always shoot down people's suggestions and explain why ffxiv should stay the way it has always been. This is the usual response here.

I already play a game with an infinite exp system. PSO2 converts any levels beyond the current cap into ex-cubes which you can spend on items or enhancements. It doesn't force people to play more because there's no reason to grind out huge amounts of cubes, it's just nice to have something in exchange for what would otherwise be wasted exp.