Actually, no I am not. If I am making any assumptions, it is that they will NOT be pilotable at all and essentially can be considered a player controlled version of Jacques (effectively a station that can do a point-to-point/system-to-system jump). The cost of jumps may make it unfeasible for an individual to do them on a regular basis but that is besides the point.But you are assuming these fleet carriers can be piloted by a single Commander just like any other ship.
As I have already pointed out even solo or small groups of explorers would have use for refuel/rearm/repair facilities away from known space. There are currently a few limits to in-the-field repairs and rearming that would make a mobile station like facility an ideal solution.