People make way too much out of OHL stats.
The Saginaw squad is heavily tilted towards offense in a high scoring league and they have a lot of elite scoring options on their roster. Every night they are trying to outscore their goaltending and their defense. Their team is one goal off of first place in OHL scoring, but fifth from last in goals against. A team with as much high-level talent as they have would normally be one of the top teams in the league, but they are only 4th out of 10 in their conference.
Misa has certainly done everything he could to be considered a high pick and he almost assuredly will be one of the first two off the board. But Schaefer is a more elite defenseman than Misa is a forward.