He's also been able to deliver some awesome experiences, though, you can't just forget everything that he did because of a software drought or some bad sales.
While it's true that the same errors have been repeated over and over, it's also true that he's been able to fix them. We don't really know what the plans for Wii U are over at the Nintendo HQ, but I'm sure none of them is thinking of being quiet while the interest in the console slowly fades away.
They have to take a step in the right direction and if that means providing a huge amount of software, I'm sure they'll do it. We all know they don't have the force to do it and as previous proofs there are external collaborations which lead to such beautiful games as The Wonderful 101 (poorly commercialized, but that's another story), Lego City Undercover, etc.
All they have to do is getting an awesome series of games on the system, once it's done you'll have a few followers coming not only for that particular game, but also all the other released software it has to offer.
As someone said earlier, the system is not missing games, there are plenty if you like the genres, what it really misses are system sellers, and Super Mario 3D World alone wasn't enough.
Will Mario Kart 8 turn things around? Probably not, but it'll surely bring some people aboard, as Super Smash Bros will, but it still misses something and that's Iwata's job to find out what it is.