I dont expect him to play like MVP Rodgers, especially now. But he would be a significant upgrade when healthy.
Is Rodgers a much better QB than Zach? Absolutely. I don't think you're going to find a single argument against that.
But to be an upgrade, he has to be able to perform. Behind this line, with a supporting cast of pass-droppers, backs that run like it's 2 foot deep mud, and clowns committing brain dead penalties, it's hard to imagine he'd have significantly more success. 4 plays in is ridiculous, but I find it hard to imagine he'd have remained healthy all year on this team.
My argument against Zach is that he can't raise up guys around him, and Rodgers is the opposite. But it's hard to do that from your derriere, which he'd be on a lot with this team.
Anyway, I didn't want to get into a big argument about this. I don't think any of us would rather Zach be out there than Rodgers--Zach included.