Very, very different players.
Sanderson, if he hits close to his ceiling, will probably bring a style somewhat similar to a prime Jay Bouwmeester. He's going to use his speed and smarts to control the puck, set the tempo, and ultimately make smart decisions to set up the play. He's not going to bang guys around out there, or necessarily be our top point producer on defenseman --- but he's a guy you'd look to for transitional play and someone who can glide back and forth between actively supporting the offense and covering his defensive responsibilities.
So the natural question is, if he's that good, why isn't he a sure-fire top 10 pick. The answer to that is somewhat nuanced. Sanderson has taken his game to a new level over the course of the season, but he didn't necessarily begin the season at that level. Likewise, there are guys who have maintained their level over the course of a season and it's hard to justify dropping them.
I think you also have a prospect who is playing in a role that doesn't necessarily result in eye-popping numbers, nor in a league/system that tends to produce those types of numbers for a lot of defenseman.
The other knock against him is that he's a prospect you're projecting, more than simply going off his track record. So there's a risk factor there --- do you believe there's even more room for growth there, or do you think he's merely closed the gap to get closer to his actual potential?
There's not a clear consensus there. Some people could have him as high as 6-8, others might have him in the late teens. But I think his most likely target range is probably in the 10-14 range.