This is the biggest problem with the game. It feels absolutely terrible to spend all your orbs getting one of the best units in the game only to find out its IVs are terrible rendering the character largely useless. Who at IS thought that was a good idea...
Probably the people who want as much money as they can get.
Ironically, they have a greater chance of getting
less money out of me than if they made the IV system a lot more fair (either get rid of it completely, or give us ways to further train our characters if we get stuck with a sub-optimal one). I just don't feel like throwing money at the game, where if/when I do get the character I'm chasing, it'll likely have a nature that renders it less capable of doing the job it's intended to do (-ATK for a damage dealer, for instance). However, I realize that I might be in the minority when it comes to this. I've seen more than a few people pull numerous of a certain character (on Reddit and other forums), chasing down that IV/nature they want. As for me? The moment I get the character, I'm done. I got Ike on his banner, after a 100+ orbs, and he was -ATK/+RES. I didn't spend a single orb more trying for another one of him.
If anything makes me quit this game, it'll be the way the IV system is handled. I don't mind how it is in the actual games, it's whatever. But in a game where people spend money (not me necessarily, for the reasons I described above) it's a massive issue.