Needless to say I am not a fan of the new CSM codex. My issue is the inability to field pure cult armies. Sure we have access to the cults as troops but that's it. I have had no desire to play the mixed bag that is presented now. It's not sour grapes on my part, I can and do adapt to the inevitable changes to the game that come along. Plague Marines are very popular now seeing they are quite resilient and are basically jacks of all trades. The thing is we need other units to support them. We do have access to Typhus for an HQ, he has plenty of neat toys and abilities but unfortunately that's about it really. You can field a Nurghal daemon prince and you can make a good case that he is worthy of the title, it's quite good overall too... Or we could field a Chaos Lord with the Mark of Nurghal and a good case can be made for him as well buy seriously you rarely ever see Chaos Lords these days. I think there is a good reason for that as well.
Chaos terminators with the MoN blow in my opinion... First they are not fearless and second if the terminator with the banner /icon of Nurgle should die then the rest of the squad reverts back to normal Chaos terminators. We can field Chaos bikers with the Mark for T6 but it's quite expensive to do and really now it's now that great of a unit. Basically the same goes for any unit with this icon.
I am hoping for an eventual legions codex but I'm not holding my breath either. GW might eventually release one but then again they might not and if they do I reckon it won't be anytime in the near future I'm not the kind to throw up my hands in teh air feeling exasperated but on the other hand it's kind of depressing.
I am a big fan of possessed Chaos Space Marines with the MoN but I find most people eschew their use.