I never really found the ping pong tactic to be too effective, his hit range is pretty huge so its best to just spread out like normal and just burn. When we got close to transitioning him I would taunt, and then the paladin would taunt off me so it'd be on the paladin first. I'd then throw up shattering throw and go back and build threat. The reason we did this was so Chimaeron would take his time chomping on the tanks first. Paladin would tank until he got sub 10k then pop ardent defender and get healed up for another hit. (Yes Ardent Defender heal works during that phase.)
Chim would then come to me and I'd use my cooldowns to live long as possible, when I got knocked low I'd last stand to get another hit in. Then he'd go to the frost DK, frost DK died, would get battle rezzed (he used AMS to be able to take another hit when he got low.) Chim then went to mage, mage hit mirror image, chim wasted 3 hits killing his images then went to rogue who popped evasion, and then rogue tanked em til death (Though by this point Chimaeron was already sub 5% health and soon dead afterward.) The key is to keep as many people alive possible as long as possible while DPSing. So personally I found that iceblocks and feign deaths were not effective simply because it takes away from DPS time and you needa kill em before the dot gets you low.