This is desperately needed for my team as well. It is difficult to prioritize tasks, even with the filters currently available. I get asked several times a month when timezone and region sort will be available for tasks. Even sorting tasks by the same company would make the follow up process much more efficient.
If not this task sorting option, could we at least be able to sort by open tasks (by task owner) in the contact view? Using next activity date is complicated because we have multiple people touching accounts so their activities are pulled in as well.