The issue is that he is expected to be Pascal Siakam but is more like Jae Crowder as far as effectiveness than we'd like to admit.
Now, he has been pretty good for the past 5 games and I thought he was excellent vs Kyrie until the 4th quarter last night, but only Suns fans expect him to take up the slack when a superstar goes out and he simply doesn't have the chops to do it. He's a good complimentary player, but, especially this year, his defense doesn't make up for the fact that offensively he just doesn't seem to have the ability to stay consistent.
Cheese's point was that nobody expected him to be a top scorer in the league. But his defense should be better this year and I don't think it's a stretch to hope that he could pick up the slack when guys are out. Great role player, but he's not a savior by any means.