Essentially, scenarios such as outlined above can be avoided if all three jousters are dismounted and kept trampled in a very small area and the tank dismounts a bit early as starts building aggro immediately, but in most cases, people have just decided its easier to run out and reset the fight. It's inelegant and feels a bit like cheating, but it works. Due to the lack of an aggro reset and the tendency of the champions to be scattered all across the arena floor, it just becomes much simpler to run out of the instance.
It seems the dev team has noticed these difficulties. Lead World Designer Valnoth posted on the official forums to say that you should no longer feel obligated to zone out to reset the first boss battle after the jousting stage. He doesn't state exactly how this will happen. Just wiping aggro on the jousters might be enough, but it would be nice to see them form up and charge together, giving the tank ample opportunity to grab all three and start building aggro easily.
Now, hopefully they've also fixed that bug where one of the champions randomly reappears with effective unlimited health during the 2nd or 3rd boss fight and starts wailing away on the party, but if not, hey... at least we can still run out.
2n - 1 go left, 2n go right. I don't see enough DoTs! More DoTs now!
Are you ready for the return of Onyxia? With the Brood Mother being revitalized as a 10 and 25 person raid, you'll need to be sure you know everything that's coming at you. WoW.com's Guide to Patch 3.2.2 will make sure your set for the next patch!