If we did that there wouldn't be any reason to play Xerath ever again. Zigg's already has the second farthest range of all the mid champs in the game why buff that more?
The only thing I'd really like to see on him is the Lux/Gragas treatment on his Satchel charge: once cast the CD for it already starts and can just be triggered again for the detonation. This way the technical CD on it would be much less and we could feel free to use it more offensively than an escape only tool. Isn't that the beauty of it? it CAN work as an escape but it's flexible enough to be used as an extra zoning tool and disable?
Other than that he's fine, a heavily skill based damage dealer with the zoning ability of the gods