I think you are going about this wrong. I actually think everybody is going about this the wrong way. I do not like any of the ideas proposed to far. The priority system will force players who enter many tournaments to choose between certain tournaments, which means that if one tournament is more important or has a better theme, other tournaments will probably not get as many participants, or not get any good players.
As for the ideas that suggest that we randomise half of the participants, I think that this is a terrible idea. Mainly because we have no way to check if the tournament host actually did randomise the participants or not. My guess is that for the most part, all tournament hosts will just handpick the participants (choose only the good people) and say that they randomised it, which means that the newer members who live in a bad timezone will still not be able to get into many tournaments. Not only that, but if the participants actually are randomised, what happens when good players constantly end up getting unlucky and hardly ever get to enter tournaments. I for one would be very upset if I didn't get into a tournament that I was looking forward to playing in because the participants were picked randomly.
I think that something needs to change about tournament applications, but this is not the answer. If we find that many people are missing out on getting into a specific tournament, then make that tournament bigger. Encourage hosts to use slightly unusual player numbers to make tournament size more flexible (96 and 48 are actually great numbers, just play it normally down to 3 players and have a three way face off). Force people running tournaments to keep sign ups open longer. If repeatedly there are 64 player tournaments that are oversubscribed, open tournament applications and let a more tournaments in.
I was actually thinking the exact opposite of this, and I have been for a very long time (if you frequent IRC, then you've probably heard me mention this before). The problem may not be the way participants are being picked, but maybe it's the fact that there aren't enough tournaments. Now, this doesn't mean that we should start having 15 long gimmick tournaments being hosted at one time, contrary to 7 or 8. I think that live 32-man tournaments (standard OU or Ubers) should be hosted constantly at different times of the day, instead of gimmicky tournaments that last for months. This will give everybody a chance to play more overall, and it will give them a chance to play real metagames instead of gimmick metagames for a change. The tournaments forum has been getting pretty stale lately, and I think it's because of tournaments with boring themes that drag on for months. Not to mention that the standard metagames have been overlooked a lot in the tournaments forum for a long time. Tournament participants hardly ever get a chance to play real metagames, which doesn't make any sense to me since Smogon is supposed to be a competitive Pokemon community.
Even if people don't like the idea of live tournaments, I think tournaments definitely need to be shorter. The deadlines need to be shorter and maybe the participants should be cut down to 32 instead of 64. This way tournaments will take a month to finish at the most and other tournaments can be posted more frequently. In the end, people get to play more often which is what matters.
tl;dr: Less long, gimmicky tournaments that drag on forever and more live 32-man tournaments with real metagames.