I wouldn't really mind this just as long as you still automatically stop running when you start to cast. One thing that always drove me insane on XI was (since I play with a controller) to let off the analog stick at the same I hit the cast. Well there was typically that "I'm slowing to a walk... okay I'm not moving anymore" part of the animation and most of the time I would get up to 70% cast before realizing that that slight extra step caused me to interrupt the whole cast.

One of the things I absolutely loved about casting in XIV was that it forced you to stop when you started casting even if you had were running/auto-running. This simple thing made playing a mage tremendously less frustrating and I'd like to see it stay when they make this change. Then it will just be Run>Run>Run>Hit button>Forces you to stop running and start casting>If you're still trying to run (on purpose or on accident) then after a brief delay you can start running again and interrupt the cast.