I don't think Iwamoto is a candidate. He directed Wind Waker HD until Fall 2013, where Zelda Wii U was probably close to 1 year in development. Maybe a planner, though.

Shikamata who did the 3DS game, I don't think he is considered a true project leader just yet.

Also, as we are talking about Yamada, I just looked through the A Link Between Worlds credits and I'm pretty confident Yamada didn't work on ALBW. He and Yasuhisa Yamamura are probably only listed under field planning because both worked on the original's A Link to the Past overworld, which was planning design-wise copypasted directly into ALBW. Both were the only Assistant Directors/Planners for ALTTP and Yamamura after 20 years out of nowhere suddenly working on a Zelda game again doesn't look right to me.

If that's true, that could may be be a sign that Yamada is full-time on Zelda Wii U since the project started, because he didn't work on anything else since Skyward Sword. Maybe he is the co-director with obviously Fujibayashi being the other one?

We might see him pop up on Star Fox or Zelda or Splatoon next year. Who knows.

Yamada is probably assisting the dozen of planners each Zelda title has. I don't think he is doing much on the design-side anymore.

Splatoon
Mario Kart DLC Set #2
Mario Maker
The Legend of Zelda
Star Fox (Project Robot / Project Guard)

We may still have a surprise or two in the form of Animal Crossing, 3DS, Apps, or EAD Tokyo. Very exciting.

But yeah, most likely false hope. Looking over all the key people (planners/designers) that worked on Skyward Sword and apart from Ryuji Kobayashi, it seems like literally everyone has worked on other EAD Kyoto/Tokyo games in 2013, while obviously someone would have to be hands-on director for Zelda Wii U. I actually don't see any other planner that could be co-director or sub-director, as they were all assigned to other projects. Looks like Fujibayashi is doing it all by himself again.

To get this out, I feel the core problem with Skyward Sword was not Fujibayashi, but the lack of multiple sub-directors for dungeons, overworld and so on, certainly like in most past Zelda games and, well, every other popular & successful development studio. Instead, the director, in this case Fujibayashi, has dozens of planners that design each facets of the game off-hand individually and then Fujibayashi single-handily has to somehow make it work. It's not a real and genuine team effort who are all 24/7 immersed into making the game, as well as trusted by the director and instead you get some past NSMB & Wii Series staff to work on designing a Zelda dungeon.

Of course, this is how EAD works. But I feel this is an actual problem within EAD Kyoto as a whole, where the only constant is the director, which is in charge of literally everything first-hand, and most of the time the art director. Though, this works without much drawback for more game-y & pure games like pretty much all the other EAD output right now, but absolutely not with an supposed cohesive, multifaceted, immersive and huge in production scale adventure games like Zelda. You need at the least a constant of a 50 people team being in touch creating together this creative effort, right when pre-production starts, just like the even Nintendo-owned development studio Monolith Soft.

We'll see, but I'd be hugely skeptical, if that's how it's going to play out again.

Skyward Sword is a polarized game. But you can not blame Fujibayashi on everything, since keep in mind the structure and guideline of the game are agreed upon collectively, with Aonuma as Manager / Producer (and Miyamoto as GM) being the authoritarians here. For example, Aonuma might say "hey this Zelda, i want our team to make it open world, no hand-holding, and orchestrated music". Fujibayashi and planning team, take it from there.

He was clearly the right guy for Skyward Sword, as the game was, at least roughly in concept, supposed to be a bigger Minish Cap; that is more linear, understandable & straightforward for the sake of accessibility. I think Aonuma clearly chose him for that very reason, but I'm not sure if Aonuma would choose him for a Zelda game with an open-world emphasis. It's not like he is a long-standing director of the Zelda franchise at Nintendo, so he is not a certainty.

Though if Fujibayashi returns as a director, then not alone. With or without Fujibayashi, I expect two game directors this time, where one will focus on the overworld, while the other one on the dungeons. Or something like that.

I'm also curious who will be in charge of the soundtrack/sound director. That seems to change with every other Zelda entry since Kondo stopped fully composing.

Staff
Producer: Shigeru Miyamoto, Eiji Aonuma
Director: Hidemaro Fujibayashi *
Art: Michiko Iwasawa *

Key: * Unconfirmed