Why not give each person their own Limit break (1/2/3) and base it off of that system? That way is does not need to be a constant thought/action we must carry out because we can only use LB's so often.

so it would look like.

PLD uses LB1 -> DRG uses LB1 (skillchain) BLM uses LB1 (MAGICBURST!)

make limit breaks something we can always have and this would be very possible.