Honestly Captive - you'll be fine

You'll have pots and sanctuary if you have a templar plus maybe even the guild emblems if your guild is high enough - and of course, all healers tend to have that end of the line cure which removes most things so I'm sure one will be a fear removal as well

Fears tend to be a pain in the @ss mainly for the TSO instances but I'm positive you'll find ways around it and do just as well as a crusader

The only thing I could probably recommend (which won't be a bad idea to pratise) is just like asg recommended - /crouch, /walk with the possible addition of a /stop as well (i.e., unhook the followers) before pulling a mob - this way if your feared, the followers stay put and can cast /cures and fear removals (without interrupts) while your running (crouching) all over the place - once the guard regains control it may be worthwhile if the slaves threw a memwipe or detaunt so the tank has an easier time regaining control (if required)

Guards are great tanks and you'll have fun on raids as they can take a hell of a beating