Ryback is a classic "monster" wrestler. Power moves, few words and lots of pain. Like Goldberg, Mark Henry and Batista before him, Ryback can be that monster.
WWE needs him to be that monster.
Monster wrestlers fill a role in pro wrestling that other wrestlers just can't. They are the ones who execute big, power moves that get fans going crazy. No, they may not be the best technical wrestlers or have the best mic skills, but they make up for those deficiencies by destroying opponents.
Ryback fulfills the fans' desire to see a beat down. Sometimes, it's exactly what people want to see.
If Ryback can stay healthy, he's got the strength to dominate opponents for years. And whether he's a face or a heel, he'll be able to execute big-time power moves. And that's what WWE wants from him. That's what the fans want.
It's the kind of wrestler WWE needs. WWE needs Ryback.