its because it would take extra dev time to make such a change. Though tbh the change to Overpower seemed like something that could have been done in less than a day let alone a few hours. I can tell it was a rushed changed because the Novice Hall NPC still says Overpower is a cone aoe attack.

I didn't realize the devs became so averse to unique job perks. WAR already has access to 3 other circle aoes at lvl 90 via Decimate, Chaotic Cyclone, and Primal Rend. Heaven forbid they make Mythril Tempest into a conal aoe to match Overpower to give the player options in any given situation. This change is proof that the dev's don't trust the players to adapt and improve on their own.