A fourth protective fighter class, the inquisitor was proposed as the 'psionic tank'. The design apparently involved high arcane resists, and could therefore be useful against spell casting opponents. However, it has not yet been implemented in the game, nor has any date been set for its inclusion.
Fessius made the following post on the official forums explaining the Vanguard developers' attitude to the class:
The idea to add the Inquisitor and Berserker classes has not been abandoned completely. However, they are not on our radar as anything we'll be doing in the near future.
- Fessius (7 June 2007). What ever happened to Inquisitor and Berserker?, Official VG:SOH Forums. Retrieved on 16 November 2007.