The quirky attack speed calculation was a poor player experience for those not in the know
What? Then put a note in a tooltip or skill description: "weapon IAS affects this skill more than others," done.
This is a flimsy excuse for nerfing a build, but it's one that was used extensively in D3. It'd be great if blizz worked with the assumption that players aren't stupid.
I have a suspicion though, that they're trying to homogenize some of the systems and calculations because they plan on adding either a new class or new mechanics.