Wow, that's a lot of tasks. Either you've got the busiest schedule on the planet, or you're one of the many folks who are big "list makers".
Unfortunately, I'm unaware of a way to sync tasks based on priority or any other criteria, although it would be nice if MS added that function.
However, another poster recently recommened some software to help organize lists that lets you categorize and make sub-lists. (Great for keeping lots of project oriented items separate, including grocery lists, etc...) You may want to check it out and perhaps move some of your stuff to it. Then you could use the Outlook tasks to reference the larger projects, and the list software for all the sub tasks. Just a thought.
http://heavenly-st.kbib.org/
Good luck!