I am looking at tasks in several lists, but in one namespace. I would like to have a view where I can reorder (prioritize) tasks from several lists. Filters do not seem to work for this purpose, because I cannot reorder items in a filtered list.
Should I be using only one list, and differentiating items using labels instead of lists? I would have preferred to have all of these tasks separated.
Right now there’s no way to do what you’re looking for natively. You can use the workaround you described but that will only be a workaround.
Tasks cannot be reordered in a filter because a) it is possible to have tasks from read-only lists mixed together with tasks where you have write permission in the same filter view and b) the position depends on the positions of the tasks before and after that and uses a per-list setting. Its nearly impossible to rearrange them in a filter while keeping the order they have in their particular list.
It might be a better idea to use Vikunja’s priority field and then create a filter for e.g. all tasks with high priority.