I'm totally aware of the fact that it would be bettor for infopop that their products are similar. Especially since threads is considered as the next step for classic owners, and they don't want to loose functionality either.
I'm also aware of the fact that probably most people like having their sites cluttered with small icons, scrolling text, bouncing images and whatnot. But I for one hate it. It is actually one of the reasons that I've always liked threads as both a user and an admin. To me, it feels like all this abundance of extra meaningless things are used to hide the fact that the real content isn't good.
The thing is, that not many other forums have the threaded view, so they can use simpler forms of showing information. More features means more possibilites of problems. But as I said, as long as no functionality is removed it doesn't really matter to me. Not now when we have the wonderful templates.
Another way to do it would be to keep the options open, let the admins decide what they think is best. If they want two icons per post, let them have it, but those who just wants one can have it also.
As far as the yellow/orange icons go (even the book) I don't like them either even though they are very threads-specific. We used our own images before, but now we use the folder icon from an old version, which is changed to bright red for unread posts.