The problem with this is demand for Chemist doesn't seem to be that high. Blue Mage and Dancer demand though is through the roof. So you fix the tanks and DPS with new highly requested stuff, but healer kinda gets left out. Sure it gets a new job, but at the same time there's not a massive demand for it, so people are more likely to swing to it. Plus, Chemist being ranged wouldn't break the formula as much as Dancer being healer allowing for a melee focused healer. Every one (including your Chemist suggestion) puts you at range, safely away from the group. Dancer healer would break away from that, having you swing and swoon through the battlefield. And as they've shown with Dark Knight going from DPS in previous games to tank in this one, they aren't afraid to change things up in this game. So yeah, as much as I appreciate your suggestion and it's very well thought out, I am going to have to disagree with it.