I think we already had a few threads about the combo merge subjects. It's kind of controversial, as some people are for it, some are against it.

Of course it would reduce button bloat as well, but it wouldn't even help jobs that don't use combos, like casters and healers.

So I thought I'd suggest combining some abilities, like SMN/Bahamut or the Ley Lines thing. It wouldn't be such a big change, and 1 button less per job (or 2 at max) wouldn't make the game simpler, just improve QoL without changing too much.