As one of the "newbies," (I've got seven accepted out of 14 shots uploaded), I felt I should weigh in with my opinion about lower upload limits for people of my ilk...
...it sounds like a good place to start.
Being completely honest for a moment, people like me--who are new to aviation photography--really *shouldn't* be putting 30 images into the queue at once. If you do that, you:
1. don't get the advantage of using feeback from shots 1, 2, and 3 to improve your subsequent uploads, and;
2. have little incentive to carefully self-screen.
Now I'll admit that my overall 50% rejection rate is a bit high, considering I'm not new to photography. Big moving objects present challenges that you don't encounter when you're used to photographing landscapes and buildings. But I've improved a LOT since those first few uploads, and it's mostly because I'm self-screening like mad (I don't think I've ever had more than about 5-6 shots, total, in the queue at once) and using the wait time to look at everyone else's work. It helps.
Alternately, an upload limit based on some sort of point system--maybe a combination of the number of shots in the DB
and a ratio of rejects to acceptances--might get people to be more selective.
Just some food for thought,