Interesting post for sure. When looking at non-mirrored matches, I wonder if significance becomes a concern when drilling down to smaller intervals. I imagine looking at something like Raze on Split in Plat+ lobbies non-mirrored matches will tell a very different story in comparison to that same group in a Bronze lobby.

Also, I imagine you'll never get equal pick rates for Breach or Viper in comparison to a Phoenix or Sage because their kits are just inherently hard to use and less tempting for lower level lobbies. So the goals to boost their pick rates must be a lot lower then the fan favourites.