I think people give way too much credit to Iwata. He was a genius game designer and seemed like a good man. He also certainly did show some great leadership by cutting his pay to help workers.
Wii sold a ton, but lacked in some ways. During Iwata's tenure, there were tons of droughts during different times. The Wii U was filled with droughts, and the some of the other platforms had them too. Iwata was running Nintendo when they went on ID claim sprees and started the Creator's Program.
Still, he probably is the best leader of Nintendo. He seemed to have a lot of heart and was responsible for some great times. But even as Nintendo's best president, he's pretty good at best. The Switch certainly proved in some ways he was going to get Nintendo back on track.
But had the successor to the Wii U failed and Iwata was still alive, I think he should've been removed as the head of Nintendo. But in all fairness, I would say that about anyone in that position.
Unless there's something missing in my assessment of Iwata, I don't think Nintendo would be too different. I still think we would get droughts here and there and still some of the anticonsumer practices Nintendo takes part in.
Lifetime Sales Predictions
Switch: 144 million (was 73, then 96, then 113 million, then 125 million)
PS5: 105 million Xbox Series S/X: 60 million
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima