BrianDavion wrote:
force weapons dealing mortal wounds COULD have a bit of a side effect that isn't good so it's something worth examining (my fear would be suddenly Librarians are the ultimate melee unit or something

) but I do think giving
GKs some sort of anti-invul save ability could be really useful at clawing out a intreasting niche for them. If the answer to "well he's packing a lot of re-rollable 3++ saves" is "luckly I brought grey knights" that'd be good for
GKs and proably shake the meta up a bit.
Well,
GK also have gak
AP out of melee, for the most part. It doesn't matter if you ignore the Custodes 4++ if you don't pen any of their 2+.
Mortal wounds is really your only solution, and it's a bit dangerous to go whole-hog in on. A bonus
MW from nemesis weapons and psybolts that wound, or roll X to wound might be nice.