The problem seems to be that the phone aspect and computer aspect are both important.
I think that much frustration arises from the fact that there should not be a problem for N900 also to be an excellent phone.
For example this call list thing: does it really mess up the whole UI design if the user is given a change to filter the messages by their type by for example adding small icons (for missed, called and answered calls) on top of the long list? These icons could be clicked and after that the call list would be sorted according to call type? Could even the icons separating the call types act as these "buttons"?