I'd love to get skillchains back, but it doesn't seem very likely with the current set of abilities.

I don't know why they decided not to use skillchains and subjobs from FFXI. Both systems were really great and gave you more versatility than equipping the same few skills on every class and waiting forever till the limit gauge is full.
I think they went too casual with the system because of players which just want to smash their own combos instead of playing as team.