That is promotional art. There is some gameplay footage, and some people have actually had access to the beta, so it's better to go off that rather than what the neck looks like in a really old promotional image if you want to speculate on the quality of the game.
Everything is still a work in progress and, even if the necks were like that on release, I don't see how it ruins the whole game, especially when toris can be modified anyway.
The game is getting a new engine because the old one is 13 years old and the new engine is what will allow things like 4 player matches to work. The new engine doesn't mean it will feel nothing like toribash. Isn't exactly rare for a new game in a series to have a new engine.
People are getting their hopes up because new features like breakable objects, the ability to break away from sticky grabs and four player matches could really improve the game. I think it's too early to predict that the game will have no chance of survival, and you might as well try it when it is finally released.