So I tried soloing MoP raids in prepatch and it turned out suprisingly well. Things were doing much less damage to me comapred to WoD (have no idea why) and even if they managed to bring me down, shadowmend with masochism topped me in 3-4 casts. I thought with removal of DP and overall damage decrease there would be huge problems with soloing, but the only boss whom I killed in WoD and didn't manage to kill in prepatch was Animus due to removal of cascade.
Honestly, I miss cascade, it was a beatiful spell with huge impact. I wish they replace MS with it and make it refresh dots or something.