This definately needs to happen, and not just for the above reasons. Casters need to get new life in this game. as it is, most soloers AND shells are going JA heavy and this creates major bottlenecks, especially against "time of day" proc mobs. IF the magic proc rate were adjusted upwards it would expand both the jobs that can be used AND the prey which can be targetted.
If the adjustments to Perfect Defense and Embrava are any indication, you seem to be trying to end the reliance on Zerg for all content, why not dynamis? And if you need a balance argument, you need only look at the jobs that are used in Dynamis by soloers now-pet jobs and any fast TP melee job/dnc. Mages are largely excluded and even nin which can proc magic mobs generally don't try, because the chance of success is so much higher on JA/WS mobs. Take the hint.
Lastly, there are alot of players in this game who loved their casters, but have been forced to largely abandon them due to everything being Zerg; giving them a viable outlet outside Aby can only be to the good, and not just as a !! proccer, but a viable source of damage in their own right. Seriously, people just want to be able to play their favorite job and still have utility and viability. Maybe you are trying to do that in the new expansion, but that's not here yet, the rest of the game is. So how about some relevance NOW?