What part of "there is no one sufficiently different to replace him" do people not get?

The only option for those who want change is a comeback from Arakawa, the guy who ran NoA way back, and there's no reason to believe he wants to come out of retirement or be associated with Nintendo again. The rest of the board is all on Iwata's side.

I dont get why people call for Iwatas head, his track record has been great. Wii-success, DS-success, 3DS success, Wii U-sales flop, but enough time to turn things around. Was Iwata in charge during the Gamecube/GBA years?, if so again Kudos for gaining profitably during that tough time too.

I really believe Ninty will make adjustments to their sales forecast after the holidays. I think their strategy right now, is to hope there is not enough PS4 and X1 during the holidays and people will buy the Wii U instead and catch lightning there

I believe iwata became the CEO of Nintendo around 2002 or 2003 mid way through gamecube's life 

He's a terrible "analyst" who isn't a bit objective and couldn't make a prediction to save his life. Remember he said the DS, 3DS, and Wii would fail. I guess after always betting against Nintendo, he will finally be right about the Wii U having serious problems.

3DS is not a success as its predecessor. Sure, it leads its segment but the DS had a 30% bigger installed base during the same period of time. Thats a lot. In other words, their portable business is down. Not to mention the catastrophic first year of the system. That was incompetence and lack of foresight. The same goes for the Wii U. Get Iwata and Shigeru out of the company. Their time's done. They are doing a lot of damage.

That's hard to say, most people on the internet didn't know who Iwata was when he was hired or knew him very obscurely. He was a minor member low down on the board of members at the time I believe. We have no way of knowing who's qualified. I wouldn't neccessarily assume that everyone at Nintendo agrees 100% with Iwata or Miyamoto all the time either, they may have just been muzzling their opinions. It's a stretch to think everyone at Nintendo thinks exactly like Iwata and no one has any ideas of their own, more likely most people at Nintendo just go along with what Iwata/Miyamoto think because to oppose them would likely is career suicide at Nintendo. 

Nintendo could also just hire someone from outside the company. 

That said, I don't think Nintendo needs to do something that extreme. What they do desperately need is a CEO for NOA/NOE that understands the Western markets, understands marketing in the West, understands game development from a Western POV, and has credibility with Western third parties. And this person needs to have real power within the company, like Howard Lincoln and Minoru Arakawa did back in the day, not a lame duck NOA figurehead who just goes along with everything the Japanese division says. 

Iwata needs to learn to delegate to the Western division and need to take input from those divisions more seriously. 

Credibility?

Only money is what convinces the 3rd parties. Nintendo could be run by DK who trows money-barrels to people, and they would be happy. The problem now is that Nintendo unwilling to pay for basic support. It has nothing to do with credibility.

Iwata has taken full control of NOA at this point. Let's see what he does with it this holiday on the marketing field.

The market has changed since the DS days, the 3DS is thriving in a much tougher market which now includes tablets and smart phone. Look at the Vita to see how hard it is to crack the handheld market these days. i agree the 3DS first year was incompetent but measures were taken to ensure a quick turnaround. Thats why im giving Wii U time before spouting doom and gloom, Wii sprinted ahead and fizzled out but Wii U could be the marathon runner like the PS3 was. IMO this upcoming gen will not see sales like last gen and that goes for all gaming companies.

"How is the Ninendo eShop?"

Well, OK I think, I don't know how to answer this.

"Are there some good discounts on full games?"

Currently all Ubisoft-games are reduced in price (40-60%). Also Resident Evil is reduced by 40%. Some downloadable-only games too, but I think you meant only retail-games.

"How do you put credits?"

Well, I use a credit-cards. Could also use Nintendo eShop-cards, which are physically available in some shops. I don't know how well that works in different countries. i don't know how you do it in PSN. But with the credit-card, I can put money on my account in some predefined quantities or by adding the amount needed to pay for what I currently want to buy. Nintendo get rid of the Nintendo-points and works with real currencies now.