I'm not quite following you, or you're not quite following me, or something.
When I say that that was intentional, then I mean that that change was made on purpose. They redesigned WordPress to work that way. When you publish a post, yes, it takes you back to that post in the editor. That is by design. That is the way it is supposed to work.
Yes, it was not like that in 2.6, but it is like that now. It is not a bug, it is an intentional design decision.
Most people don't write one new post after another after another. They write a post, then notice a typo and edit it, or add bits to it slowly in draft mode, or what have you. So the Publish button takes you right back to the post, in case you notice a mistake in it. It's the most common use case.
You think it is inconvenient to not get an automatic New Post, but many people thought it was inconvenient to have to reload the editor every time to see the post they just wrote.