Ok....

Reduce cd for manafiction by 15-20 seconds

Reduce cd for acceleration by half

add aserious number of enfeeblements, cleanses, beneficial abilities, and staus effect spells into the usable cross class abilities list for all casters (paralyze, stone, poison, float, dispel, et cetera)

Battle mage stance (45% increase in all potencies/durations, but doubles mp costs of spells for 20 seconds. Cross classed to all DoM)

Pre-charged spell casts (passive) that continue at 50% cast time for up to three different spells as long as the cast bar exceeds 65% of cast time to activate (once active pre-casted spell will begin at 50%, nextcastof same spell will be normal cast time), all DoM. This will allow DoM to prepare for emergencies or begin combat with burst damage.

Chain reaction spell combos (RDM only). Ex: Fire+wind=verfirecane. Vercure+wind=vermedica. earth+thunder=vermagneto. thunder+vercure=verregen (7 seconds)

The Versignal (passive): if Black or white gauge is below 25% at the start of combat: gauge below 25% will start increase to 25%

Um, just pick three or more of these, and it will would definitely increase DPS or any DoM QoL