Do it, do it nao!
I am planning once we start getting more folk dinging at least 55 to start boosting Molten Core gearing runs, I'm sure I can get a couple of other 80s along to get the job done too.
Here's my bear spec if I'm needed to tankify Rawr!
Are you sure Furor is worth the 5 ranks you could've otherwise spent on 1 rank in Improved Mangle and 4 in Rend and Tear (wchich is awesome)? At level 80 60% of my damage comes from Maul and it's a huge part of my threat. I don't think 10 extra rage at the start of a fight will be equal to that, especially not since you can start out with ~30 rage anyway.