Assassin is perfectly fine the way she currently is. In my opinion, she's actually much stronger than the Wraith when playing correctly in pretty much every mode. Making mistakes is far more punishing, but the highs you can hit playing Assassin are simply amazing.

The Romerus is no slouch, and if you use it right, especially the charged right click, you can put out some massive damage. It's harder to aim than the Spektor, but if you're accurate with it you can absolutely tear people apart. A fully charged right click can net you 275 damage which is enough damage to one shot a large part of the LawBreakers cast.

Assassin movement is the peak of speed in LawBreakers. You just have to maintain your charges properly and utilize your dashes and grapples in conjunction correctly. Not to mention, blindfiring with the Romerus in Zero G provides fantastic speed. Wraith movement is easier, but it can't match the speed the Assassin can hit.

For objectives, most people are seriously slouching on the the flux blast (assassin grenade). The flux blast knocks people and projectiles back, and does a small bit of damage. One of the places where this ability really shines is blitzball pushes where you can use it to knock back the enemies standing on the goal and get the goal much easier instead of taking a kick to the face as you come in.

The Assassin is a much harder class to play than the Wraith, but it's no slouch when played correctly. In the tournaments played so far, the Top 2 teams have been pretty much running the Assassin exclusively over the Wraith.