I think it is very interesting that this list of pros and cons are only from a Government/employee perspective. If you were to reconsider the pros and cons of engaging citizens from a Citizen/customer perspective I think it would be quite clear that it is way better for THEM, even if it might cause a little more work for us.
I really like the suggested solution to advertise engagement as a solutions tool, not a complaint tool. Although, I don't think it is the public's job to present solutions to the problems they identify. I think that is our job, mind you this is just a matter of opinion. I can't deny it is WAY more helpful when someone presents a criticism in a constructive way, but if the Government was being criticized a lot on a certain topic, the volume of complaints should identify an issue that needs to be improved don't you think? I think better listening and understanding could lead to better solutions to the problems.