I disagree that downvotes are the answer to the problem you raise.
With downvotes in the current system a whale could upvote the return, upvote the ones they like, and downvote all other proposals. Then the barrier to entry for a new proposal would be FAR FAR worse than it currently is.
You can't just slap on downvotes and say "yep everything will be fixed now". You will have the same issues, only exaggerated.
There's nothing to disagree on regarding downvotes as I never said downvotes were the solution.
One account should not be able to vote on more than a certain amount of proposals and there could be a predetermined floor instead of relying on the return proposal to fulfil two functions. The return proposal was necessary to ensure the pool didn't get robbed by selfish proposals, however, allowing whales to actively control its level is neither fair nor ideal.
A fork could say proposals will not pass if they don't get at least x votes from at least y people, considering active hive. Everything below the floor will be returned to the DAO. The return proposal was a stop-gap measure to cover an oversight in the SPS/DAO and should be made permanent and fixed, or floating on some level based on some pre-determined function of active hive.