As I'm not plugged into D&D discourse for the most part, I have no idea what classes are actually stronger or anything. I assume that they left out aberrant mind because they maybe felt it didn't quite work. Having a sorcerer that potentially gained their powers through the tadpole on top of everything else could have been too deep a connection compared to all the other classes, though that still could have been fun. I personally wanted the Shadow Magic bloodline, it sounds cool. But so does Storm sorcery so I'm happy. Also I'm guessing Karlach will be a wild magic barbarian and that's why they picked that one.