User blog comment:Willbachbakal/(Champion Rework) Varus, the Arrow of Retribution/@comment-25228021-20150501160206/@comment-1330314-20150501162230

That's sort of the point: Blight is a core mechanic for Varus, but even more so for AP Varus, where it defines his burst. I removed AP Varus's on-hit steroid, but instead gave him the option to detonate Blight stacks far more frequently, which would establish a clearer distinction between bursty AP Varus and DPS-heavy AD Varus. I also made sure he scaled well enough with the base damage on his abilities to retain some of his ramping power in lane, even if in the end Varus would be weaker early on.

In the end, I think AP Varus's strength should be fully oriented towards his burst, which he'd be able to access a lot more. If he wants more DPS, he'd have the option to build, which I think would be core on him anyways. While the E change may not make immediate sense, it would be a buff to his Blight mechanic, since he'd be able to use the extended range (it's not 100% global, per se, since it's limited by Varus's cast range and movement speed) to lay down autoattacks before activating the zone to detonate his stacks. Basically, even though I removed an AP-scaling effect, the new active I gave him acts as an extra source of AP burst, and would allow him to access it a lot more often.