I think the necromancer daggers need some love. Especially our offhand dagger is under performing atleast in my opinion.
Our offhand dagger is supposed to be a defensive condition offhand. Condi transfer, bleed and weakness support this idea. Hence i would suggest the following. Add some lifeforce regen (maybe 1-3% per hit foe) to deathly swarm (dagger 4) and rework enfeebling blood (dagger 5) in to a two stage skill:
First skill: Dark Armor: gain protection and dark aura for 4-5 seconds. (Cookdown: 25-35 sec)
Second skill: Enfeebling Blood: can only by used while the dark aura is active from dark armor and it destroys the dark aura to bleed and weaken enemies around you. (Essentially the old enfeebling blood without range, but maybe also nerfed if needed).
My reasons for those changes are: Offhand dagger is the only necro offhand without any lifeforce regen and its 5th skill is kinda lacking and needs some changes, so adding protection (a boon core necro can have more off) and the dark aura is a nice buff to its defensive ability and it would give the necro a weapon skill for the dark aura, like eles get weapon skills for their auras (fire, frost, shock and magnet) and mesmers with their staff 4 for chaos aura. That way all scholar professions would get an aura on thier weapon skills (currently necro is the only expection and dark aura wasnt always in the game). Also having a proper defnesive skill on a core necro weapon is needed (one that doesnt rely on hitting an enemy).
For mainhand dagger, i think it is in a somewhat decent place but has bad synergy. With that i mean all skills are technically decent on their own, but i think dagger 1 doesnt work well with dagger 2 and 3. Hence i would suggest a rework it to a 400-600 range skill in some form (maybe something like the ele dagger 1 skill in water but instead of vuln you get life steal).