Every profession has different ways of mitigating damage. For ranger, it is mostly centered around evades, especially on weapon sets. The problem with dagger and PvP is that this melee weapon offers no evades.
For comparison, we have sword hornets sting and serpents strike are both evades.
And greatswords power stab (auto) and swoop which are both evades.
What should happen is to keep with consistency dagger 2 and 3 should be evades... that being said, perhaps just dagger 3 can be an evade due to its charge system, you can use it twice.
As it stands now, dagger has low mobility AND no defense making it unusable in PvP. How this was released as still not been updated is just another drop in the ocean of design frustrations.
It's pretty simple, ranged weapons don't really need evades. Melee weapons for MUST.