The problem with your way to thinking is that you assume that they can't make a 2D Mario with something actually new that wasn't in any way in Super Mario Maker. Now I'm not saying it's easy. I've been thinking quite a while about the same thing and, honestly, if it was up to me, this would indeed be the end of the line. I could add new mobs and stuff, but in the end it would be just the same with some differences. But I believe that Nintendo and their creativity can overcome this and give us something completely new. It wouldn't be the first time they did this.
Nintendo loves to live in their comfort zone, but every now and then when they leave, they throw us some something extremely creative and good that you just can't deny that talent that they have. So they will surprise us once again with the 2D Mario. Whether it's with the next game or the one afterwards, I don't know. I'm waiting.
And to the people saying how the selection of the levels in Mario Maker is bad, well I agree for now, but I think that in the future, we will be getting more and more good and creative levels and less of the bad or auto playing levels.
The people that aren't that good at making levels will slowly move on and find other games, the fanatics and talented people will keep playing it. And every time something creative is found, someone else will use it and make something even better and more creative. Not long ago people didn't know how to make boss battles properly, now we have checkpoints and boss battles through the same mechanics.
Every now and then the 11/10 piece of magic comes out and inspires a lot of new levels, good and bad. But as time moves on, only those really dedicated will stay and they will keep making better levels.
Johnny Novgorod said:
Another way they could raise the stakes would be to foray into a new genre. We have platforming, racing and RPG. Is a Mario shooter/strategy/stealth/survival iteration completely out of the question? How far can you move before Mario stops being Mario?
Splatoon was initially thought to be a Mario shooter. But the team felt it would be better as a new franchise rather than a Mario spin-off.
And Mario stealth sounds interesting. Bowser realized that kidnapping Peach means nothing if he doesn't deal with Mario beforehand so he has stolen all the power up of the kingdom. With Mario being weak, he has no choice but to take the slow and stealthy route through the Mushroom kingdom.
A strategy game would play from Peach's perspective, she would control the Mushroom kingdom's army of mushroom to defend against Bowser's invasion. Thought that ones too violent so not gonna happen. More of a Zelda type of game.
Michael Prymula said:
I disagreed with Yahtzee when he said that New Super Mario Bros. Wii was a game that had "no right to exist", but I think that criticism definitely applies to Super Mario Maker, in my opinion it is the very definition of a game that has no right to exist, I just can't fathom why anyone would want to pay 60 dollars for a level editor, it sounds like a waste of money to me.
I think you should thank NoA for that. In Europe the game was like 40 euro, same as Splatoon. Not a full retail price.
Also go on youtube and watch some creative levels and you will see why it has every damn right to exist. People have been asking Nintendo for a Mario level editor for years now. Nintendo delivered (well not 100% as many wanted but still in a pretty good shape).