nichopoleve
Warlord
That seems unusual. Even with stock v17 you should be subduing regularly. Once you get your Hunting promotions it should happen fairly often in fact. I haven't had any problems with subduing since v17 so not sure why you are experiencing that.
Non-hunting types have a much lower rate of subduing, so spearmen, axemen, etc. are more likely going to kill the creature than subdue.
Is hunting promotion a must btw?