Yea I'm sure all western developers hated Iwata. And it's a premature conclusion. We don't know the amount of support the switch will actually have until it's been out for a while.We're talking about third-party support.
Could you care to explain why some 3rd parties with historic of antagonism against Nintendo like EA, Take-Two, Epic and Bethesda decided to support Switch after it's biggest flop when they ignored for most of the time it's most succesful platform of all time (Wii)?
Yamauchi was well known to be hard boiled and unfriendly to third-parties. He said he deliberately ordered the N64 to be hard to developed to repel untalented third-parties away. Iwata followed that strictly unfriendly management style toward third-parties at his tenure, especially against western devs. No secret why western support shrinked considerably toward GameCube days.
Devs aren't stupid. They won't ignore a userbase of >100 million because "the hardware is bad" or whatever. The reason why devs ignored Wii was because they had issues with Nintendo and their management. Otherwise, they would have mass supported it. Devs are now supporting Nintendo because there isn't someone in the head of the company antagonizing them.
Of course it's more complex but here are two reasons:
The Wii couldn't run ps360 games even if it wanted to.
The Wii U sold like shit and was hard to port to.