Personally, I felt that Leylines should have been a circle that moves with you, but we all know the devs were never going to do that.
Or just actual Leylines. Cast Leylines, a overlay shows 5 different cast points on ground in the battle area spread out.

One grants reduced delay, the other magic potency boost, the other lowered MP cost, the other adds a dot to casted spells, the last one grants an extra sharpcast. Between the Lines would take place of Leylines until the LL cooldown is refreshed. BL used to cycle between the different leyline. Would still be a caster who has to stand to cast but at least you would be more mobile.