I haven't watched him a ton, so I can't comment, but this really doesn't match what I've read from others when talking about Moose Jaw. I always heard that Yager was playing third or fourth fiddle to Mateychuk (especially), Savoie and Firkus. But I don't have a large enough sample size of watching to gain a firm opinion myself, that's just from what I've read.
Regular season, it was pretty clear that Mateychuk was the best player on the ice 85% of the time. Playoffs, I felt Mateychuk was the flashiest but I felt him and Yager were about as effective as each other. Firkus was really good, quite noticeable all the time, just not as crisp and efficient as Yager. Overall play, Firkus and Yager were pretty similiar, Yager just has an offensive flair that Firkus never had. The difference between putting the puck to the right areas and putting the puck right onto the right sticks. Savioe was a clear step behind those other 3, they tried Savioe between Jagger and Yager but Calvert was far more effective there, instead they put Savioe on the second where, even then, Kovacevic drove the line for much of the playoffs. Most telling to me was when Moose Jaw was pushing play late in one of the Warriors/Blades games, they double shifted Calvert a couple times rather than trusting Savioe.
I'd hear out an argument that he played second fiddle to Mateychuk, it's not the worst argument that Jagger and Yager were somewhat comparable for a while (though I don't agree), he definitely wasn't a secondary team player like Savioe, Calvert, or Kovacevic though.