You can DW the same relic/mythic/aeonic/empy weapon through lockstyle.

Anyway I'm not sure we should compare the time spent for Master Trials (wether it's worth it or not, it takes a bit of time to set it up) to the time they would have to spend to add a simple option/command to turn off the glow effect from RMEA weapons.
I'm really having a hard time believing it would take them more than a couple of hours of a single programmer's work.
Doubt it would change anything in their plans for the month.