Great question! I feel that it is okay to post everything that is already public information. In a past life, I was the Community Manager for a Saas company and we would always talk about product features or upgrades as soon as they were released, assuming that competitors could find this information somewhere else online or by purchasing our product.
When we were talking to customers about future product releases we would let people know we understood their pain points, and were working on a solution. If they asked detailed questions (which was not very common) we would respond by being honest and letting them know we were still working on the product upgrade and would announce it on the Community first when it was complete.
I think it's okay to post your downfalls on the Community because if your competitors are smart, they already know what they are. The good thing about acknowleding your weaknesses is that your customers know you are listening, which is the whole point of an online community.
I am curious to hear your thoughts on the subject as well!