Largely a moot point now, since I try to eat fast food sparingly, but boy do I wish they had all day breakfast when I was in my early 20's.
You should figure out your TDEE, macronutrients and micronutrients and base meals off of that. Burger at 8am? Who cares if it's what you need.
The product line is the value McDonalds provides to it's customers (the franchisees) if that value decreases then the money it gets paid by it's franchisees in aggregate decreases.
Also, liability for the fast food workers would be with the franchisee and not the corporation. I don't know in the US but in my country, if you have more than around 50 employees or you are a public listed company, you are held to much higher labor standards than of you are a small company.