I like the idea. I know that it will take long for people to get used to the idea that there is ONE (new) iinbox for suggestions and that they'd better check if their request hasn't been done before if they want it implemented someday
But if the rules are clear, they will gradually get there. Of course there will be the eventual noob that will make a wish out of place, rant about not being listened and all that, but for serious contributors, who understand that this is beta, that this is freeware, and that we are but humble helpers (and big winners) of Steven's efforts, this could be a valuable tool. It's easier to count votes for a feature like this than to manually count all the "+1, cool idea, dude!" around.
Still, as Steven suggests, people won't organize by themselves. We might need a curator; someone who helps weeding out the suggestions and merge together those that are redundant or complement each other, as well as telling people "your feature has been implemented: check here and here..."
Show of hands? Maybe I should raise mine. Really, Steven, if you think something like this could work, I could give it a shot. Think about it.