The last 2 games he was a designer on are Steel Diver and Wii Music. Looks like he's more of a manager than a creator these days.

i'm talking consoles. the people are voting with their feet. their home console isn't selling anymore because their offerings don't hold the same appeal they once did. 

The 3DS is better. So they still have their magic touch on that side of things although that market is dying fast. 

I think it's a combination of Nintendo as a whole not doing well and Miyamoto being unable to create amazing games due to struggles within Nintendo.

Nintendo does really well at being Nintendo but the last gen really screwed Nintendo up by creating a bubble which popped (a lot of the Wii buyers were one time buyers that never went onto supporting Nintendo or any other console). Nintendo tried to recreate that bubble and failed and was caught between not knowing what to do, do they try harder with the gimmicks, do what Nintendo does or try compete with Sony and MS.

I still believe the last great console Nintendo made was the N64. It wasn't just the console, but the games they brought to the table.

The WiiU has been such a mess for Nintendo, the panic seems to have filleted down to their game development and affected that too leading to the creation of Metroid, Starfox, a delayed Zelda which fans are still waiting on, and only one 3D Mario.

Unlike other peers Miyamoto has such as Carmack, Peter Molyneux, Hideo Kojima etc, he isn't free to develop as he pleases, but is bound by a console, what Nintendo consider to be best for that console and what he must incorporate into the game.

Possibly. One could argue that he could have left and gone solo or put his foot down, but that's easier said than done. The main point is that Miyamoto is only as good as Nintendo is. If Nintendo does poorly, it will affect his output as the problems will trickle down and this is precisely what we have seen this gen. 

Honestly speaking, for Nintendo I'm not sure. If you ignore the Wii and look at N64, GameCube and WiiU sales, it seems it is a core fanbase keeping Nintendo going. That isn't necessarily a bad thing as if they deliver what the fans want they can still be successful. 

I think Nintendo needs to go back to its roots and cater to them instead of 3rd parties like EA etc. They need the 3D Marios, Zelda's, Lylat Wars, Pokemon Stadium, Harvest Moon, Banjo Kazooi, Goldeneye etc.

They've done it before, there is no reason why they can't do it again. However, that's what I want from Nintendo. What someone else wants might be entirely different. 

I feel like we're looking at this wrong. It's not a matter of whether Miyamoto is losing his touch or not, but how he functions. He's a creative type of person who is often questioning how people play things, trying to think of new ways to do things, making things fresh, and he's always been a guy about gameplay over story. That's why Miyamoto tries new things with many projects he works with. A lot of the games he works on having something new and fresh to them. He's a person who draws potential ideas and inspiration from concepts, game mechanics, and even from life for making games, which has resulted in some hit titles.

Though Miyamoto's need to create new methods of play doesn't always work, as some things he made weren't so great, such as Wii Music. Though, it's great that he continues to try new things, and this isn't just limited to games, but also gave suggestions for the DS and the idea of Miis.

Miyamoto also seems to have a knack to see the potential in other people's ideas, giving support and suggestions to help them grow, even now he had a hand in making Toad's Treasure Tracker a full fledged game. He's also helped with other games, little ones like... Pokemon, Kirby, and Metroid, and we know how some of those games turned out...

I could probably go on with this. He's great to challenge as well, which led to games like Majora's Mask and Link Between Worlds, with Eiji Aonuma wanting to make new games over remakes/enhanced versions. Sure, Miyamoto's getting old, is probably done with creating new hit IPs, and should retire, but hey, the guy still does some good work and is good to have around... Most of the time. Nobody's perfect

He lead the team, Pikmin 3 is his project.

Thats far more involment of him than he had with Paper Mario: Sticker Star that OP mentione like proof of "Miyamoto lost touch". He also did not directed Star Fox Zero, he was just one of 3 producers.

Pikmin 3 is his project and that one of best Nintendo games of this gen.

One failed console doesn't mean they lost touch with games, Nintendo has tons of great games this gen.

Who should replace him?
On a bad day Miyamoto is as good as most other developers.
On a good day he is legenday.

Miyamoto role is become only to guide young developers.