Every player and commentator outside of Dallas or on the Cowboys will tell you that Wentz is a better quarterback than Dak. The advantage Dak has is he's been healthy. Based on the best ability is availability, then, sure Dak is better than Wentz. But if the experts who've played the game say Wentz is better than Dak, I'm going with them.
Besides, this argument is always cyclical. When Dak gets an advantage, posters come on this forum and crow about how he's better. But they were strangely silent when Wentz was leading his team to the best record in the NFL until he got hurt.
When both are healthy, Wentz is the better quarterback. But Dak has the better offense - the better help, if you will.