Guys, I don't think simply giving more shots or range for his ult actually works there. The ult itself does not capture the essence of Xerath's lore. Pressing that R and firing 3 or 5 arcane shots does not make him look like a being of pure power trying to release himself.
I guess changing how Xerath's ult turns him into an arcane piece of artillery can fill that gap in the lore. Making his ult having charges (like Akali) to demonstrate the buildup of latent energy (even with more particles and lighting on the model to show everyone when he is able to go nova) and allowing the champion to fire those shots independently would do wonders. With this a Xerath's player could choose between using his shots for some extra poke (making it different from the new Ziggs, I will talk about it in the end) or committing all shots to try and take out a single target.
I've written on it here if you want to look at it: http://boards.na.leagueoflegends.com/en/c/gameplay-balance/epEwmj0v-is-this-xerath-change-accurate?show=flat&comment=0004
IMO, while Ziggs is less poke oriented and more of a wave clear until reaching the tower to bring it down fast, Xerath is more a poke and siege champion. He is there to punish enemies for standing under a turret for too long. While Ziggs can both use his ult as a huge waveclear and to finish fleeing enemies (or even start TFs), Xerath's ult only allows him to hunt fleeing enemies. It does not help him at all with poking or siege.