I think Necros need an Elite skill similar to the Sylvari skill Take Root. As a Sylvari Necro as my main I actually use this skill a lot for PvE and WvW. It’s my only source of damage negation.
Perhaps a copycat skill for Necros where were sink into the ground and and Summon 5 Shambling horrors and gain invulnerability & self chill for 3 seconds.