Maybe the way the bonus dibs are awarded should be the other way around -- less the first day and then increasing each day after that? (Or maybe just a set amount all the time, like .20 per request or something? Or maybe the bonus dibs could just be accumulated but held for several days until everyone has a chance to get some of the "good stuff."
I do think that it's good that someone who is offering a lot of things that other people find desirable gets rewarded for that. It's a great incentive to offer great seeds.