From a PVE perspective (mainly raiding) – Buffing Theifs damage and survivability (acrobatics) is defenitely a good start but it won’t get us into the META or a spot on a raid team in any serious capacity unless we are given a useful utility/boon that benefits the raid squad like Mesmers, Revenant’s and Warriors have.
With that being said if Anet delivers on its promise of giving Theifs higher damage and better survivabitlity it might not be a complete liability to bring a Thief to a raid like it is now.