Not really. It’s instead a different device offering an experience that doesn’t require a keyboard or mouse at all.

Why would it become worse if they add support for keyboard and mouse on top of it?

It does offer support for a keyboard and a mouse but what you're proposing is adding features or programs that would only work (or at least only work well) with a keyboard and a mouse, which would be a pretty big departure from the current design of the device.

If they don’t take anything from general experience, why do you care? Core of the system will still be touch oriented.

I am contesting the idea that it's possible to compromise the design philosophy that had guided it up till now and NOT "take anything from the general experience."