The initial change was super bugged because they didn't handle the ticks correctly, this basically fixes that. Aside from the radius increase, I think the other storm changes are only bug fixes from the previous PTR. IMO they made the patch changes too technical, should've just said "fixed bugs from last PTR". Really we just need to know what's changed compared to the stable release. I think it might tick faster than the stable release now so it might be better than half DPS?
This is now 130 damage across about 6 seconds, instead of 80 damage across less than 3 seconds. So I guess this is like 75% of the original DPS.
Mana shows storm at the start of his video, in unit tester. ZombieGrub talks about it starting at 2min in her video.