I agree on guard but necro I don't know, I would now fix first traits that are not working properly and than slightly lower cooldowns or higher some dmg output.
Guard necro are in wierd spots, while guard has indeed big bunker potential, it gets shuttled down quite fast when 2 people attack him, solo its kinda messy. Necro on the other hand scales to good with guard, necros without guard, can escape but not bunker and facetank 24/7.
I bet less healing on guard could fix necro too, since it doesn't feel that strong with other supporter