I'm wondering if these people giving deconstructive crisitism are judges or not? I know once OCReMixer has showed up at least once more or less vomiting over a wip with little else to say. Obviously, not doing such a thing should be common courtesy and not something to mention in the site guidelines or forum rules. But the truth is, the difference between the best and the worst mixer in the wip forum is huge. Should the really good mixers refrain from commenting on the really bad wips in order not to scare them away?
Should there be a wip playground for people who REALLY don't know how to mix? I don't see how it would work - the worst mixers usually think they're a lot better than they actually are, and being told you posted something in the wrong forum because it's not good enough would be as effective at scaring potential mixes away as anything.
As for what makes a good melody, I'm not sure if there's a way to come up with a definition that everyone can agree on, and it's certainly not something I would ask OCR to do.
I agree some people need more guidance, but the problem would pretty much solve itself if most people spent more time in the wip forum. I know I haven't been there a lot lately. But, and this might come off as disconstructive critisism, not everyone is capable of making good music no matter how much training they get, just like with anything else (becoming the world's fastest runner, an astronaut, or a magical wizard). If you don't have a feeling for what makes a good melody, then maybe writing music isn't the best choice for a career (just like if you don't notice if the drums and the melody in a song are playing at different tempos - it's happened right here on OCR). In your case, you have what it takes, even if you're not yet good enough to make something to pass the judge's panel. But not everyone does, I think.
I like the idea about one-on-one lessons, but are you suggesting people who already have mixes on the site would offer lessons over the internet in exchange for money? That the judges should do it as a means of bringing in more money to keep OCR running? I'm not really sure where how much money OCR makes is of any relevance (also, it's barely making enough money to keep the ship sailing, as far as I've been told).