I think a slight buff to storm is worth experimenting with! We've definitely seen fights where protoss blankets T or Z with storm but still loses due to the relatively low damage output of storm. For this reason, I don't think fights will be determined purely by how many storms are landed.
I think there might be early game concerns of storm drop being pretty strong, but tbh storm drop is so weak right now (warping in a few zealots seems to be far better) that I think buffing it won't be game breaking.
Overall, i'm not sure if this is a buff or not for protoss, but I do think it rewards higher skill play more.