I feel like there are no good options after defeating lords in battle. At first it felt like an accomplishment, when I finally had an army capable of defeating other lords in battle. But after playing for a while, it seems pointless and repetitive.
1. Release the lord. Get a small boost to relations, but the same lord is back on your door step the next day.
2. Capture the lord. Because of how quickly they get released, this is essentially the same as 1, just delayed and without the boost to relations.
3. Execute the lord, watch 5 straight minutes of relation decrease notifications, and be hated across the entire world.
I feel like I either have to become hated (which makes recruitment impossible after a while) or fight the same battles over and over again. As a small independent kingdom, it's near impossible to successfully maintain a siege for long enough when doom stack armies re-appear in a matter of days. Execution seems like the only way to make any progress in wars as a small kingdom.