Yeah this fight sucks, I just got it with a fairly well geared group (mostly AF+1, glowy weapons, etc). My iLevel is 58, I have the DL body, AF everything else, Astral accesories, and an http://xivdb.com/?item/2051/Alkalurops.
We could NOT beat this fight to save our lives. I'm not sure who was at fault, the BRD was keeping my MP up until right after Amadine spawned, then turned that off, the BLM was having issues avoiding the targetted AOE at times, but we managed to kill Amadine each time and then she starts spamming the final move and usually I would drop first and the rest would follow. She cast it several times on us as well. Am I correct in assuming Blood Rain doesn't fire if you kill the adds fast enough? It could be we weren't killing quickly enough then.
I parsed the fights, the last one which we got the furthest on the BRD was 161 and the BLM 181. No idea what those numbers mean though