Sidebars are actually much more than that, they can be used as "containers" almost anywhere in a theme.
Example: Sidebar with Category Cloud Plugin in the header of http://www.eliZZZa.net/
It would not need much change to spread this idea:
* Call it Widget Containers
* Let us give a Sidebar an alias name (for internal overview)
* It would help to have an administration function, allowing to choose how many "sidebars" one needs from within the Widget administration, without having to change functions.php
What do you think about?