I've always seen our Enhancing skill being the highest as a way to ensure that our en-spell damage is the best in the game. The only enhancing magic that gets better qualitatively with higher enhancing skill are all self target, combat spells. Phallanx, Enspells, Stoneskin, Gain Stat, and Spike spells all get something from higher enhancing.

Better Spells and abilities out shine what we can do in that roll. With one exception. Phallanx II you can cast on others. Look we have a job in a party. Huzzah! What is that, MNK > PLD? They would like Phallanx II? There you go. Now get up there and stab that mob in the face so that it dies faster. IF you don't like doing that then go level SCH. It really is what you are looking for and is an exceptional job.