I lost my first game of Doms II against the AI, after my pretender tried to run away from an attempt to break a siege (which results in automatic death
).
I would
expect that an immobile pretender would be incapable of routing at all, which would be a nice unique and logical advantage for them to have.
It might also make sense to give them an advantage thay they can't be preached out of existence without actually destroying the fountain/statue/etc.
I don't think being immobile is of itself an unworkable problem. In fact, it's a cool option. They might deserve a look though to see if they need to be given any extra abilities or adjusted costs compared to the other options.
PvK