I think this would be a nice feature to have down the road. Maybe allow thralls you have on defense to mount player owned horses and fight on them during battles, and give them to NPC exiles for mounted patrols and scouts around camps to bring more pressure during raids on NPC camps.
AI would probably need a big overhaul so this is more of a in the distant future kind of suggestion.
The Dev team addressed this in one of their streams. They don’t want to look at thralls on mounts until the A.I. is improved. (Implying that they are working on A.I. but not out right saying it.)
Did he mention what their priorities are in thrall AI development? I’d like to see village behavior and maybe the ability to open doors that aren’t locked or break down enemy doors. There’s a lot of things I’m excited to see done with thrall AI actually.