Alright, now you've done a bit of work to backup your claim. However, you said, "Nintendo's really the only major publisher who let's most of their studios keep partial ownership of the IP." That would mean you've analyzed a large number of games by all the publishers, at least enough to come to a conclusion. I'd like to see the side-by-side comparisons, if you don't mind.
Regardless, what I don't really understand is the idea that co-owning an IP means Nintendo "trusts" developers more. That doesn't make any sense. That still means Nintendo controls the fate of that IP. Nothing can be done without their permission. Why does that imply trust? Wouldn't "trust" be funding a project while letting the developer retain full ownership of the IP?
For example, I believe Fuse is owned by Insomniac--wouldn't that make EA more "trusting" than Nintendo? Sunset Overdrive is also owned by Insomniac--doesn't that make Microsoft more trusting? Off the top of my head, I'm pretty sure Titanfall was owned by its developers before they sold out to EA. Not that it really matters, as the contract is the important part.
Actually, if you want to talk about trusting, wouldn't Activision win? Destiny is solely in the hands of Bungie now that their partnership is over.
I've got to be honest, here. Taking partial ownership of an IP seems less trusting to me than some of what we've seen elsewhere.