Between suggestions and the bar, i dont think its needed. It would seem more like clutter. Simplicity in the forum makes it easy for new people to post. It also removes the hassle of searching through the forums sections/threads/sub-categories to find a relavant forum. A perfect example of this is the ubuntu forums. There are categories, with sub categories, with even sub-sub-categories. It makes it a pain to post, especially when you get hassled for posting in the wrong section. Because of this when i post there, i just post in beginners, with the first line "sorry if this post is in the wrong section". I do this just because i dont want to take the time to look through all the sections to find where i should post each time based on my question topic. While also not wanting to get hassled for posting in a relavent section but not the "best" section.
But i dont know, maybe others would disagree.