i am probably mistaken. but i am pretty sure there was an icon for article view in earlier builds. and discussion threads too... all threads in similar thread box had some or the other icon. like the thread view. i guess not. would play around with a test build running an earlier beta to clear my doubts. please close this bug report!
haha alright. thread view with just first post is still a bit confusing. hard to tell if you are in a question thread or discussion thread. no visual indicator. there is a bit extra space below the question thread (above quick reply box) iirc compared to discussion thread.
In terms of the XFES side of things, there isn't really a bug here as it just uses the standard XF template.
Though as you noticed, we wound back some of the thread type icons in mixed thread scenarios, though that mostly applies to not diplaying discussion thread icons (or icons for thread types which don't define an icon internally).