I've been playing with the change since patch and I've ultimately found that I think this is for the negative.

Red Mage was distinctly different from the other casters by needing to manage a lot of movement to sneak in melee combos around mechanics. While this gameplay is still there during downtime, it no longer matters during burst. This lowers the skill ceiling for the class and makes it act nearly identical to the other casters. Take the savage fight against Sugar Riot, as an example. While learning and failing adds phase, I was forced to forego most of my burst while we figured out the fight. Later, my static and I found out how to position everyone so I could sneak in melee attacks during burst - and if I didn't get it, it was my fault. Now, Manafication acts as a "delete positioning/timing mistake" button - the only value it has during burst is a singular (albeit 1200 potency) oGCD attack.

With both Black Mage and Summoner becoming very mobile over the last several patches, Red Mage's sole gameplay difference is balancing mana. While this isn't a great place to be in terms of job identity, I would be willing to accept it as long as all the casters did similar levels of damage at the top of the skill ceiling. It is not thrilling to come to the realization that your favorite caster isn't Black Mage, and therefore is effectively nerfing a team.

Anyway, since the devs are clearly committed to this change, I'd love to see these two follow-up changes:
1. When under the effect of Manafication, spawn an aetherial version of the WoL in melee range doing the attack, because it'd look cool
2. Do more to equalize DPS within a role so we can focus on the playstyle of a job (balancing Black/White Mana, singing songs, draining MP) rather than just bringing whatever has the most DPS for the patch