I guess with it only being Kylo, it didn’t bother me that no one else talks about Palpatine during the bulk of TLJ. To me, the First Order doesn’t know until the broadcast. There aren’t really any other lines of dialogue except trying to escape and then Rey & Leia on the Falcon at the very end. Then TROS starts with finding the message, and everyone on Ajan Kloss asking if the Emperor could really be back.

If you can think of lines from TROS that could be added to the films earlier, I have clean audio for it to work with. It just doesn’t feel necessary to me.