Yes, you are focusing on the runs provided, understood. As I've said repeatedly at this point, all are viable choose who you prefer.
For me the opening pair is set. Marshall and McGrath easily not only the best bowlers ever, but have the most diverse skill sets compared to each other. They compliment each other perfectly and test every part of a batsman's technique. They are also the two most winningest bowlers and took their teams to the pinnacle of success. That might mean morning to you, it does for me.
Philosophically it feels wrong to omit a bowler who is arguably the best, because of their batting, especially considering they are going to bat at no. 11.
So that leaves the 3rd.
Imran's home and away split is higher that for anyone else in his era and his away record is poor in comparison. Especially when he encountered easier conditions away from home. That raises concerns and for me, and not trying to convince you or anyone else, he isn't quite in the same league as the other two. In what was a bowling era he averaged 28 in Australia and India, 24 in England (pass for the first tour), 26 in NZ, 25 in the WI, so yes he's out. It doesn't matter how good his batting is if I don't think he's as good a bowler as the others.
Hadlee is for me no doubt the 3rd best bowler ever, but for me he's (along with Ambrose) a bit close to McGrath stylistically and would prefer Steyn's aggression and reverse swing. Steyn isn't better, but a better fit.
So yes, I may lose out on batting, but I think I make up for it in compatibility, skill set and intangibles.
You are free to disagree and as someone said, there's no wrong answers. This is just my take on the situation.