My current tier list of companions
There are no bad companions in the game, which is why the last tier is MEH, and I still consider those worthy to be kept around, Yrliet is perhaps the most questionable of those.

Cassia is held back by her intromissions in dialogue being only about colours
Abelard is held back by a rushed act 4
Marazhai would be top tier if he wasn't so hard to justify keeping him around
Jimmy is very good but his character arc feels underdeveloped because act 4 is, again, rushed.

Pasqal is perfect
Good comedic stuff, good cool badass stuff, interesting commentary, companion quest deeply tied to the main plot, he's just a very cool companion all around.


https://tiermaker.com/create/rogue-trader-companion--15921526?downloadedImage=true