We tried this, because I was somehow bored from the wotlk content so far. Its nothing special to clear sunwell on lvl80, but with 10 players only its something interesting again! You have to stick to the old tactics 80% of the time and the bosses are overall more chellenging than 90% of the wotlk content so far!
So to say, sunwell 10man is a perfectly tuned 10man-raid-instance ;)
Its just fun! Try it!.