So, after attempting this last night on 10 man, I think blizzard had a serious oversight, as they seem to be doing with 10 man's and making them substantially harder on 10 then 25.
The reason this particular encounter is harder (much) on 10 man then 25 is that on 10 man heroic the Abberations have 1.8 MILLION health compared to 25 man heroic which only has 2.5 million.
To put this in perspective, you have 15 seconds of the green vail doing 100% increased damage, so essentially on 10 man you need to pump out 900k regular damage in 15 seconds.
We have world ranked DPS in my guild, we are not even getting close to 50% on these adds. Like 60~ sometimes 40 if our DK rapes.
But back to what I was saying, bringing 5 DPS that's 1,800,000 divided by 5 which = 360000, divided by 15 (15 seconds) = 24000 DPS per person on EVERY add, this isn't single target burst, this is AoE burst of 24,000 per add. So if you had 9 adds (standard) that would mean each person would be pulling 216,000 DPS. See the problem?
Now compare that to 25 man. They have on average 16 DPS, so that's 2,500,000 divided by 16 which = 156,250, divided by 15(seconds) = 10,416 DPS per person on every add, x 9 adds = 93k DPS, which is much more in line with burst AoE DPS.
Now I for one am tired of 10 mans getting the shaft by blizzard, we DONT get a tier token from heroic halfus like 25 (meaning there's no heroic tier upgrades for us), we had to use a DPS tank on chimerean just to get it down and now this ridiculous amount of DPS needed in order to do a certain mechanic in a fight.
This obviously means we're going to try and kite it next time we go in there, but the fact that we have to do an encounter the "unintended" way to kill it (which seems to be the norm on 10 heroic) is getting really old. Tune it really well, but don't make us bring 3 tanks to 10 man on fights like halfus, or make a DPS tank and taunt, or make our DPS do 216,000 DPS per person over 15 seconds. Come on Blizz.