i was one of the worse players at SOD and I got 9th place because of easy brackets (because it was randomly seeded). I have to let you know that I was greatly disappointed in this because I did not get to play many top players in the tournament. The best experience is tournament experience, and if random brackets doesn't give me that opportunity to play against top players, then I don't want to go back to SOD. What use is it for a low-level player to get easy brackets? That won't help me improve much.
I think it would be fair to all players if SOD did proper seeding. That way, the low-level players can get their experience, and top-level players can get accurate placements. You said that you do random brackets to give the new players a chance, but the new players enter the tournament already knowing that they don't have a chance, and that they are entering so they can get experience and hopefully have a chance in the future.
To do proper seeding, do it based off doubles results like many people said, or do it based off a knowledgeable player's opinion. You said you can't do that because of a potential new player that might be really good. Well the point of seeding is that you deserve a good spot in the brackets because you have already established yourself as a good player. The new player might be good, but he hasn't established himself, so he shouldn't get any benefits.
If it's because you simply do not know how to do seeding, you can just ask any of us. We don't want to bash you, but instead to help you and make the SOD series a better tourney experience.