Add an inventory slot(s) to cages that allows for untamed thralls to be placed. Cages would then appear populated and have a purpose other than decoration. Alternate route would be to still provide an inventory slot to equip a broken thrall so I can have spare thralls have a purpose.
Maybe my wheel of pain is full. Maybe my taskmaster needs a break. Maybe I just want to use my thralls for decoration but I can’t put them in the cage after spending 20 minutes trying to figure it out. GIVE ME CAGE THRALLS FUNCOM!