Xeraths real issue riot seems to miss

I've made many posts before discussing the lack of support artillery mages really seem to have. Such as Keystone, items geared toward there playstyle or lack of build paths. However riot themselves seem more content with this portion and concerned that he isn't seen at higher elos. As someone who has been fluctuating between plat 3 and plat 2, Xerath's defining issue at higher elos is how easy it is to dodge his abilities or especially his ultimate. It is also why we don't see fellow artillery mages doing well in higher elos (looking at ziggs). Most champions have some form of damage mitigation, heal or dash incorporated into there build. Not as if there is anything wrong with this, however when you limit artillery mages spell hit boxes to small diameter. You can easily expect the amount of spells to have missed, increase as you climb the ladder. I myself don't have a current solution to this other than increasing the hit boxes. However you will never see artillery mages at higher elos with straight damage buffs, there are to many champions that can close the gap and nuke them...