I feel for account  progression you need a solid  Revivor to help carry your account  through content. 

Scyl of Drakes would  be  my choice  if  that were  my account list of champions

I agree with PG.  Scyl is definitely a strong choice.  She is an amazing progression champ with heal, revive and solid Crowd Control for wave progression.  I would've taken Scyl to L60 before Loki.  

However, if you did any of the event for Artor and have a strong awakening for him, you could make an argument for him before Scyl. 

Artor and Scyl both good options.  Wallmaster id make an immediate priority as well.  

I 6starred scyl