Hard disagree because again the are factors you're overlooking such as WiiU was the jump to HD development for Nintendo which alongside having two platforms to support forced that situation as well as the figuring out of the blue ocean market, you're giving the current leadership credit for following groundwork that he laid down for them while having to come up with the solutions to problems that even the biggest competitor in gaming threw in the towel over. Following an instruction manual well doesn't make you better than the person who wrote it by default, the current leadership would need to make several impactful calls of their own like Iwata did before even being considered in his league only Yokoi and Yamauchi compare to him in that regard.

I don’t think it was Iwata who had planned a resurrection of Metroid Prime, 2D Metroid, Mario Wonder, Emio, etc. You’re treating him as some messianic figure when during his tenure it was nothing but troubled waters outside the first few years of Wii. Meanwhile Furukawa has led Nintendo Switch 2 to the highest of highs in the industry’s history amidst stagflation of all things!

Again, yes, it was a smart call to combine studios, but when the games you call for are Nintendogs 2, NSMBU/2, Pilotwings 3D, DKCReturns 2, Mario Party 9/10, etc. and you sanitize all your brands to be as commercially recognizable (but without much soul) as possible, that’s not what I’d call a successful leader. Iwata is when Nintendo went from TTYD to SPMario, Smash Melee to Smash Brawl, Pikmin 1+2 to no Pikmin for an entire generation, etc.

I appreciate this thread, and I'm not even disagreeing with you, but your thesis is wobbly. You focus mostly on the software pipeline, but you don't dive deeply enough into the games developed during each leader's tenure. I think it's unfair and incorrect to characterize the totality of Iwata's output simply as tepid variations on a theme, and Furukawa's output only as bold, expansive, and comprehensive.

Just to break some of these things down:

1) Iwata focused on developing pre-establish system-selling IP (e.g. look at Wii and Mario during Wii and Wii U: It was all Mario!)
Well, look at Switch: Super Mario Odyssey; Mario Kart 8 Deluxe; Mario Tennis Aces; Super Mario Party; New Super Mario Bros. U Deluxe; Super Mario Maker 2; Paper Mario: The Origami King; Super Mario 3D All-Stars; Mario Golf: Super Rush; Mario Party Superstars; Mario Strikers: Battle League; Super Mario Bros. Wonder; Super Mario Party Jamboree; etc. Plus at least five Zelda games. Plus Animal Crossing. Plus a bunch of Pokemon games.

And what about all the out-of-left-field projects green-lit during Iwata's tenure: Brain Age; Wii Sports; Nintendogs; Tomodachi; Rhythm Heaven; Splatoon; etc.

2) Furukawa’s focus has been on expanding, bringing life back into dormant IP (e.g. just look at the NS1/NS2 generation: Famicon Detective Club, Switch Sports, Mario Strikers, Metroid Prime 4, 3D DK, Kirby Air Riders, 2D Mario/Zelda, etc.) 
Iwata's reign gave us New Super Mario Bros., the first brand new side-scrolling Super Mario game in 11 years. It gave us Pilotwings Resort, the first Pilotwings game in 15 years. It gave us the first Glory of Heracles game in 14 years (and the only one released outside Japan). Also, why does Furukawa get credit for Metroid Prime 4, but we don't celebrate Iwata for Metroid Prime 2, 3, and Hunters? Or Metroid: Zero Mission? And why give props to Furukawa for 2D Mario and Zelda? We got a lot of those across DS, 3DS, Wii, and WiiU. And why pay tribute to Switch Sports for bringing back the vibes of Wii Sports and Wii Sports Resorts, hallmarks of the Iwata era?

Again, I'm not necessarily disagreeing with you. I just don't think your analysis thoroughly explores the nature of Nintendo software released between 2002 and 2026.

Edit: corrected the name of Metroid Prime Hunters

The argument isn't that Iwata had no failures, the argument is that Furukawa has no accomplishments and had not to face any serious challenges. You cite  economic problems as challenges, but Nintendo faces them currently just with the brand power and current momentum alone. This isn't very stable long term. Let's see how Switch 2 fares after the price hike. Also the economic pressures apply to the competition too.

Iwata had failures, sure, but multiple accomplishments, with Wii, DS, Switch and a lot of innovative software. The idea of Miis and Tomodachi Life was signed off by Iwata. Furakawa cannot be credited with the success of the Switch, as the launch window was already planned when he took over. Realistically you have to calculate a few years before any decisions a new leadership makes are even visible to us. At that point Switch was already a runaway success.

Furukawa had not overseen anything new so far. We see as new IPs Nintendo Switch 2 Welcome Tour (a concept that Astro's Playroom did better), DragxDrive (clearly a failure) and Pokopia (designed in 3rd-party partnership, but to be fair so is Hyrule Warriors in Iwata's time). In hardware we have the idea of mouse control (which I don't see catching on, at most they are optional in games like Metroid). Nothing really new.

Iwata had to face the challenge of the failing WiiU. His answer were new IPs, which were very successful (like Splatoon). WiiU games generally did very well once transitioning to Switch. Which shows how much Iwata did right.

While I like that Nintendo is now revisiting old IPs (like Rhythm Heaven, Famicom Detective Club, Wii Sports, Starfox, Donkey Kong), I feel the lack of anything really new. That may turn out to become a problem in the long run.

That doesn't make any sense. WiiU and Gamecube were the core gamer consoles.

What are you talking about? In Iwata's time fall the development of Miis and Tomodachi Life, of Splatoon, Mario Galaxy, Super Mario 3D World, Mario Odyssey, Art Academy, Wii Sports (and follow-up games), Xenoblade Chronicles. You name NSMB as a problem, but it was actually in all instances very successful software, even NSMBU clearly outsells Welcome Tour and DragxDrive, the Furukawa era games. Iwata had massive success on software and this drove in big part the success of Switch. Switch was called out for all the ported WiiU games, that this drove in big part it's success. Mario Kart 8 is the best-selling Mario Kart.

How do you even conclude Iwata fumbled software?

I think Curl didn't answer the initial comment because it couldn't be answered the way you phrased it. Basically the idea that was presented and what Nintendo was promoting to an extent that Wii Sports was a gateway drug to hardcore gaming was just wrong. People who wanted to play Smash Bros already played on Gamecube. To be fair, Brawl expanded upon the consept which was likely to appeal to a broader audience. Wii had lots of different type of gamers of which some overlapped and some didn't.

I think a big design flaw with Wii was that it didn't have a HDMI port or 720p output. This was huge problem with the upscalers and A/D converters of flatscreen TVs 15 years ago. 

I'm treating it as it should be on objective merit across the board while you're focused on some of his mistakes, your reply here highlights my point for example you praise Super Mario Wonder yet it was Iwata who brought 2D Mario back after more than a decade the is a good chance we may not have Wonder now as a result, you mention Prime's resurrection yet it was Iwata's leadership who made Prime even exist he even gave the green light for another branch of the franchise to be given a chance in Other M which as flawed as it was brought the 2D mechanical pace to 3D, same thing with Pikmin.

Even the games you're downplaying are down to your personal opinion as in general they're well received by many, Brawl to highlight a point is the base template for every Smash game since including Ultimate, Nintendogs not only was pivotal in engaging the blue ocean market but showed a willingness to allow experimentation in software and pursuit of new markets who today are very much integrated in the Nintendo Userbase. Even series like DK it was Iwata's leadership who made serious strides to keep the franchise relevant, the current leadership have done nothing to even be compared to him and that's what it comes down to as Iwata faced economic, brand, software and market challenges across a long period and against strong competition, Furukawa could go on to do the same but as of right now he took over when a number of problems were resolved and the level of competition has decline in comparison.

If your answer is not Yamauchi, you are a lost cause.

I think Iwata was the most charismatic and most sympathetic. He had very high highs with the Wii and DS, but also very low lows with the WiiU especially...

So i think overall, Yamauchi was by far the best and most successful, even though his last few years killed a lot of his good doings from before.

Furukawa is doing a good job so far, i agree he hasn't yet put his stamp on anything, but he also hasn't really fucked anything up.