I was curious as to why no slave traders no longer appeared, and then I found out that they stop coming after you've reached a certain population to make it harder to grow. While I agree with the reason behind it, I feel that it could be changed a bit.
There are now numerous ways to make money in the game, but slave trading is by far the most fun compared to crafting and loot selling! While being sieged and assaulted can be very dangerous, it's a great opportunity to make money by trying to capture, healing and then selling the bastards as slaves. Because this seemed so fun to me, I had set up a fine prison with tables, chairs, decoration and fancy carpets and a high standard medical ward for prisoners only. But now that slave traders no longer visit me, I feel so cruel when using my awesome prison and medical ward just to harvest organs. Just seems so cruel!
Therefore, my suggestion is to make a tweak to the slave traders: have them arrive randomly, just as the other ships, but make them (at a certain point) no longer sell slaves while still buying them!
There are now numerous ways to make money in the game, but slave trading is by far the most fun compared to crafting and loot selling! While being sieged and assaulted can be very dangerous, it's a great opportunity to make money by trying to capture, healing and then selling the bastards as slaves. Because this seemed so fun to me, I had set up a fine prison with tables, chairs, decoration and fancy carpets and a high standard medical ward for prisoners only. But now that slave traders no longer visit me, I feel so cruel when using my awesome prison and medical ward just to harvest organs. Just seems so cruel!

Therefore, my suggestion is to make a tweak to the slave traders: have them arrive randomly, just as the other ships, but make them (at a certain point) no longer sell slaves while still buying them!