Okay, now that I've (and lots of other people) used it a bit, there's one main problem: unlike the default "Post Title" that appears there, this fix makes actual text appear there. With the default, it disappears when somebody clicks there, allowing them to type a new title without removing anything. However with this fix, the "Add a title to your post" is actual text in the field, which means it must be removed (backspace or delete), or it is included in the title. I had one user leave it on the end of their title, so it was "The Post Title They TypedAdd a title to your post", while another user didn't put in a title at all, so their title was "Add a title to your post". I'm trying to make a site that's as easy to use as possible, and if I have to choose, its easier/better to have no suggestion text in there, but use the first however many words of the post as the title, than to have multiple posts with the title "Add a title to your post."
I'm wondering if this is something that will be fixed with WP 3.1 and the P2 update that should follow? Then again, its not really a bug, if making a blog post the default, is not a part of the normal theme settings.
EDIT: It must have something to do with the blog post not being the default built into the theme, because "Tag it" appears in the tag field just fine, but "Post Title" only after clicking in, then out of, the title field.