You're not really going to be able to fuse a Persona that's completely broken unless you're in the late game, where things are usually very easy anyway, or unless you know the game pretty well, which again makes the entire thing very easy. I mean, your first paragraph is kind of a moot point, because even with chosen skill inheritance, you'll never have all those skills at your disposal anywhere near early game.
Bottom line is that randomized inheritance does nothing more than waste the player's time compared to chosen inheritance. If you know what skills you want, you just back out until you get them. There's no additional input on the player's behalf. No resource being used. It's just killing time. To use your own words, that's not interesting gameplay.
And really, the ability to make a powerful Persona has nothing to do with picking the skills to pass down. If you dig deeper into things, it's more abut how early the game allows you to have those abilities. Personas don't need 8 crazy abilities to break the game. Usually just 1 or 2 will do it. As soon as you get a Persona with say, Megidolaon, or Hassou Tobi, it's pretty much easy mode regardless of what else they have.