Imagine if every weaponskill currently limited to in-combo use (outside of, say, Meikyo Shisui or Perfect Balance) could be used freely, "combo"-ing instead based only on effects embedded in the weaponskill itself and/or some replacing "combo" mechanic.
For instance, imagine if Spinning Edge could situationally be stacked, at diminishing returns, to empower a following skill or could be timed for an evasion bonus, or Gust Blade could be used as a Wind-building skill and a gap-closer, or that Greased Lightning diminished sooner, but granularly rather than in large stack-sized chunks, and was built per cycle rather than per Coeurl skill (outside of Perfect Balance).

Essentially, every weaponskill has at least a situational reason to take up its button space at every GCD, rather than, say, having your choice of combo-path alone (per as infrequently as six times per minute on DRG).
What would that gameplay look like to you? How would you like it to function?