While I certainly don't see this as something that will turn a half day park into a full day (or a 1 day into 2), I think they will be welcome additions. While we usually spend 1 to 2 days at AK each visit, I don't think these features will really extend our park day by much.
However, the Marketplace may well become the AK equivalent of the Emporium or Mouse Gears. It will be nice if they can have mostly African inspired merchandise, and not the usual crappy souvenirs sold everywhere.
A good CS restaurant is much needed in Africa, IMO, and the African inspired menus sound like an intriguing alternative to the current CS fare. What type of food the TS restaurant will serve hasn't been announced, but its possible location next to Pizzafari may give us a clue.
The new walkway connecting Africa and Asia can only be a bonus as far as crowd and traffic management goes.
I think that these new features will really be only of passing interest at present. But if the opening of Pandora results in the increased crowds that Disney hopes for, these new additions will be of significantly more value.
But really, the only thing that is going to keep guests in the park for a longer time than they currently spend, is more attractions. And that isn't going to happen any time soon.