I have two thoughts on the matter. First, I think people will get used to NPC dialog not appearing in the chat log. It's something we all are used to in single player games (there is no chat log in almost all single player RPGs). It has some inconveniences, but if you're interested in the story, you'll probably be taking the extra effort to give the dialog your undivided attention, and if you're not, you can just look up the general info in your quest journal.

Secondly, as a matter of fact, all of the true CSs already had dialog in "chat bubbles", or rather subtitles. But either way, Having CS text appear only outside of the log is not actually something new.