Scath could get a rework with an added effect.
"increase the damage of your next fire or ice spell by 50% and increase AF/UI duratio' by 6sec"
This would garantee BLM some dps while moving without actually changing the rotation.
It would also raise the dps floor by making AF easier to keep up when u move.

Also, while this would be more qol change, I would love if SE could fuse the two ley line skills as well as fIV and iceIV