First of all, it's not an argument, it's a debate and I will give him credit for his first year, but the second was an epic fail to the point that the locker room was a complete disaster and after he was replaced by John Fox it was written about in Chicago that now they had someone that would hold the players accountable and not allow them to run the locker room.
Agreed he won't be calling plays if hired, but over his 30 year run in the NFL, he's been more unsuccessful than successful and IMHO, McVay does need experience assistants, but I would rather him be surrounded by assistants that have shared more success than failures.