What's weird about Zucker so far this year is that he's not shooting a ton less this year than he was last year. In terms of shot attempts, he's at 40 in 12 games this year after being at 57 in 15 games last year. That is less (3.33 vs 3.8 shot attempts per game), but it's not crazily so. He's just doing a really shitty job at getting shots on net, fewer than half of his shot attempts have resulted in shots (19 shots on 40 attempts). That makes me think his main issue this year is decision making, where he's shooting at shitty times and passing up shots at shitty times.
Based on the eye test, I think that is supported because he seems to be deferring to Malkin a lot and then taking bad shot attempts if Malkin gets the puck back to him. I think bumping him to the bottom-6 may do good things to help him regain his shoot first mentality. I think the issue is I don't really like any of the other options to take Zucker's spot on that 3rd line, even if McCann was healthy.
I don't think Tanev would do anything for Malkin. Tanev's entire game is "skate fast and hit people", which is basically what Zucker while playing shitty is doing in that spot right now. ZAR looked good last night, but do you really want to put ZAR on your 2nd line?