Riki Firestorm has needed a huge buff for a LONG time. It was generally agreed upon to be the worst off map there was due to the excessive delay(what was it 9 seconds?) from when you clicked to when the first shell hit. V1 is still much better for the cost, firestorm will just be usable now.
That doesn't really argue anything that I said though? From the video, the firestorm was decimating buildings on par, maybe even better then a V1. Sure it could use a buff, but it shouldn't be better in every aspect then a V1, unless a V1 is getting a buff. Either way, they fixed the Firestorm so it did less damage to buildings, which I think will make it quite balanced, and give it the proper buff.