Thanks for the answer ! I stopped watching this thread, thinking no one would answer.
Indeed my fantasy of a lone Nagash and some very elite Morghasts and Grave Guards seems compromised. I don't want to start adding small heroes like necromancers or vampires, nor cheap units like dire wolves.
Guess i'll stay on my main project of a full Ironbreakers/Irondrakes dispossessed army
Thanks for the feedback guys! It did help a lot, even if the result is me not going LoN