I wouldn't mind combining different combos into single buttons a la pvp. Mods do that already.

As a controller player, everything is possible due to swapping extended crossbars, but some classes are fairly uncomfortable to play. That would go a long way into making them more accessible and not really much simpler.

Can't do this with every class though, but RDM and DRG come to mind. Not compressing all their combos, but at least the 123s, leaving rest of weapon skills separate.

SAM and MNK get more complicated because of their rotations, though.