Literately 90% of the threads in this section have been made before. Make it a rule that you cannot make a suggestion that someone else has made which is still active. It really is annoying when 9 people make a thread on an idea you come up with after you post it.
I don't see how the user would be punished for doing this (ban, infraction points, mute?), but I do support.
I hope you realize if you make 10000 suggestion threads titled "Fix the OP glitch" will not get any more attention than one thread titled "#CypForDemote".
Thread would probably get deleted, then the user would get warned, and so on. If this was accepted it would get sorted out. Support.