You're right about input. But I doubt a touchscreen will ever suffice for a lot of professional work.
For graphics and CAD work, I need the precision of a mouse cursor. My laptop's trackpad works great, and my mouse works even better. My fingertip on a screen, by contrast, will always feel clumsy in comparison. Fingers are just too fat. The only way they become not too fat is with a gigantic screen. But then that's not really a tablet. And gigantic screens can be ergonomically bad, because they force you to bend your neck looking at them.
Likewise, for serious typing, I need the tactile response of a keyboard. Touch-typing on a touchscreen is frustrating.
Of course, there's no reason you can't attach a mouse and keyboard to a tablet. But then you basically have a laptop that doesn't fold closed. It's hard to consider that a uniquely tablet-esque experience.
For graphics and CAD work, I need the precision of a mouse cursor. My laptop's trackpad works great, and my mouse works even better. My fingertip on a screen, by contrast, will always feel clumsy in comparison. Fingers are just too fat. The only way they become not too fat is with a gigantic screen. But then that's not really a tablet. And gigantic screens can be ergonomically bad, because they force you to bend your neck looking at them.
Likewise, for serious typing, I need the tactile response of a keyboard. Touch-typing on a touchscreen is frustrating.
Of course, there's no reason you can't attach a mouse and keyboard to a tablet. But then you basically have a laptop that doesn't fold closed. It's hard to consider that a uniquely tablet-esque experience.