Let me reprint the change again here.
The changes made to Rotface were an effort to fix a bug that fell through the cracks in development and testing. The previous iteration of Rotface in 10 player difficulty used (and still uses) the same timer as the 25 player difficulty version when dispersing its Mutated Infection ability.
What this means, plainly, is that a disproportionate number of people were being put out of the fight near the 30% mark in 10 player (by a large percentage) versus 25 player, making the entire fight much more difficult than intended.
Obviously if you severely outgeared the fight, none of this mattered to you. The HP change will have no effect on your 10 player clears. You will, in fact, still kill Rotface.
We don't severally out gear the fight and we did not, in fact, kill Rotface. We fought him AFTER the change was made and about 20% life is when he started to bug out. But we killed Festergut rather easily. I believe by the way the fight is designed that Festergut was meant to be the DPS check with his hard enrage timer.
With the way Rotface works now, he has a soft enrage, but only on the 10 man version. He’s a stiffer DPS check than Festergut now.
Basically instead of fixing the error, the Developers simply reduced his hit points so that there is a less likely chance you'll see it. It's sweeping the error under the rug, a band-aid fix, and I feel it's a poor choice on the part of the development team. Rotface is still bugged; they are just hoping fewer groups will see the bug by reducing his hit point pool.
My main concern is that the Developers will not fix Rotface and hope this band-aid will be sufficient. Based on our experiences last night, it won't be. I feel like we've got a skilled and geared 10 man group. We had the server 3rd kill on Yogg. We just missed Heroic Anub by less than 1%. We know what we're doing. I feel like we got the fight down, and we would have had the kill if not for this bug. I think that if our group struggled, other groups like ours (skilled, geared 10 man guilds) will struggle with this boss as well.
Now, there might be 100 reasons they went with this solution. Maybe it was going to take longer to truly fix him and they wanted a quick solution out so groups didn't get road blocked on a bugged boss. Maybe the fix requires a patch. I don't know. I hope they fix him soon. He needs to be fixed, not band-aided, fixed.