Of course satisfactory, thank you for you thoughtful answer. Two points: 1. I tried to control for people just sucking at Horrify by focussing on upper tiers, as described in OP. This only strengthened the effect. That doesn't mean what you suggest is not there, but if it were, wouldn't it be weaker at upper tiers, where people know how abilities work and how to mostly land skillshots et c? (It could also be that your effect is present but that Horrify is easier for skilful players to get...

So lots of people have beautiful theories about the value of Rain of Destruction. Clearly, you think it's TERRIBLE. The problem with these theories is that they are rarely matched against data. There is data on hotslogs about Rain of Destruction, and the data says that while it is picked much less often, it has a higher win rate than Horrify. Attempting to focus on higher-expertise players by limiting the search to team league or the upper ranks only makes the difference in win-rate starker....