I think something very important is making tournaments more inviting. Scrubs don't want to go to a tourney, pay $20 for venue and entry, and then lose 2 sets in a row. If more tourneys, ESPECIALLY locals, had pools, then worse players would have more of an incentive to go. Not only do pools guarantee a decent amount of tournament matches, but it let's people play people with a wider variety of skill level and it also builds camaraderie within the pool, which helps retain people in the community.
Pools also remove bias for seeding in local tournaments. When outsiders see players getting seeded based on reputation it gives off the impression of a group of friends (the veterans) ignoring the outsiders (newcomers). Not very inviting at all.
Rather than focusing on getting people totally new to Smash, which is very unlikely because Brawl exists, we should be focusing on retaining those players who are just getting into it. A lot of these people are the scrubs I mentioned who show up to 1 or 2 locals then quit, but they also include Brawl players. Brawl is a huge pool of untapped potential Melee players and again, by being more inviting (pools), there's a better chance of getting these players.
Tourneys also need more exposure. A lot of local tourney series stay within a thread dedicated to that series, but what happens is nobody outside of the region finds out about them (and sometimes even people in the region don't find them). I'm not saying that these should be posted in the main tournament board; rather, their results should always be posted in the results thread. This makes even local tourneys more hype and players may look at the results and say to themselves "wow this looked awesome I really wanna go to the next one."
So yeah, pools and tourney results. Time for TOs to stop being lazy.