Not really good suggestion you didn't provide any alternative methods on how to make it easier. It is easy enough now, you just walk around with your Pokemon out, and let them faint other Pokemon; or you can catch a Pokemon with a friendball to speed up the process.
In my opinion, making Riolu wild and catchable by friend ball would 0 down the efforts taken by the player to evolve it. You can always catch it in safari and no use of making it wild I guess. You can evolve friendship Evo Pokémon as fast as your leveling up or walking just make sure you don't trade or it faints.