The problem is the entire last planet, you have this gray, depressing planet with absolutely no one to talk to. There's no party member banter to break up some of the tediousness.
That and how many dying people have you ever seen standing and chatting you up for 20 minutes before finally collapsing?
However, I just realized this is a K3 possibility thread and we're getting off topic discussing completeness of TSL, so we should get back on topic.
I'm feeling more hopeful about K3 with Hannibal's article and the not-a-definitive-no response in the chat.