Force are not short of fullbacks. They have Tiatia (incumbent), Potter (played the Cheetahs series four games and was very good), then they have Donaldson, Burey, Parata and probably Stewart that can easily slot in there.
I did get mixed up about Potter. I was thinking he was a centre but he's definitely a candidate at fullback.
Tiatia is fine but I think Campbell is an upgrade. What's more he's Aussie eligible.
I'm not in any way suggesting Campbell is about to go to the Force. I was merely pointing out that while Campbell is a capped Wallaby his path to being a starting fullback isn't necessarily better at a team other than the Reds.