The concerns about Reinbacher's offensive potential come from nerds like Scott Wheeler who think the only way a good defenseman creates offense is to skate around endlessly with the puck, dangle people and make high risk plays all over the ice, regardless of what happens at the other end of the ice.
Reinbacher is two-way defenseman, he isn't an offensive defenseman but he has offensive tools that will result in points and net positive offensive possessions when he is on the ice.
Someone like Reinbacher is always going to be a victim of his point totals reflecting the quality of the team around him. His entire offensive game is built off his skating, poise with the puck, finding the right outlet, moving the puck forward and then cycling the puck, pinching in and getting his shot through on the net. He has a good shot but it isn't a shot that is going to be a double digit goal scorer.
You absolutely pick a defenseman like Reinbacher in the top 5. He is the perfect partner for a limited guy like Matheson or Hutson. You don't find many guys his size who skate like he does with the poise that he plays with. All you need to do is throw on the tape of him at the Worlds last year to see exactly what he is all about and how good and valuable he is to a team.
Watching his point totals is not going to help anyone understand what he's capable of and it's a big blackhole in why someone like Wheeler constantly gets clowned on for NHLe nonsense.