He wasn't a gamer himself, but he understood the entertainment business very well. He also wasn't soft like Iwata and he didn't mince words. Nintendo's down era in the home console business under his watch was first and foremost caused by Sony's behind-the-doors deals with third parties and that's something no Nintendo president could have done anything about.
The most likeable for sure, but this was also a double-edged sword. After leading Nintendo to their most successful era at the time, he followed it up with Nintendo's darkest era and this happened for two reasons: For one, he was too nice to his own developers and allowed them to do what they wanted regardless of expected sales, and two, he was very gullible when it came to third party relations. His most memorable tough-guy-statement was that "third parties who don't support the Wii U now will regret it", but that was more the frustrating realisation that third parties got him pretty good than anything else. Before his unfortunate passing, he managed to plant the seeds of the Nintendo of today, including the creation of a console that third parties were bound to hate and shun. This showed tremendous courage on his part and was very much like the Wii and DS era where Nintendo was declared dead by analysts and major third parties before their systems even launched.
He came from Nintendo's financial side, so his approach will be closer to Yamauchi than Iwata. But he has yet to be responsible for a console launch himself, so by default he cannot be in the same tier as Yamauchi and Iwata. He's a distant third with the only credit being given to him so far that he managed to make Nintendo stay on course and remain committed to a successful platform throughout a generation. My personal opinion is that Nintendo is better off with a president who is focused on the business side of gaming, because great sales and great games aren't mutually exclusive concepts.
His appointment was always the one of an interim president, so he merely served as the head of Nintendo until the next big president was determined. There's really not anything you can say for or against him, he simply fulfilled his role as he was supposed to without making any major decisions on his own.