As to the non-stat-boosting items being "optional, not necessary" --
In 3.5, many posters here have taken the view that a high-level fighter basically needs to have items of See Invisibility, Fly, and Dimension Door/Teleport (to escape Forcecage if nothing else). These are not stat-boosting items, but they are SO useful as to be almost essential. And they seem like the kind of capabilities that miscellaneous items will have in 4E.
I understand that the designers want to see a greater diversity of magic items used... but will there be some miscellaneous items that are so good that everybody will need to have them?