Bracket pools are really stupid as a method of determining seeds imo. If you're using it to eliminate that's a different story but seed determination with bracket pools is so asinine.
Let's say you have a 16 man bracket pool. That means that the MAXIMUM number of people that someone plays is 6 (to get out of the pool as a 2nd seed through winning LF and losing WBR1) and the MINIMUM is 4. The likelihood of someone losing in WBR1 and making it to LF is pretty slim unless you're at a dumb stacked tournament, but let's say we give the player the benefit of the doubt of playing 6 matches.
If you split the bracket pool into two round robin pools of 8, one given person will play 64-8=56/2=28 sets in an 8 man pool. If we use "# of matches won" as a metric to use in assigning seeds, then an 8 man round robin pool is 450% more accurate than a 16 man bracket pool.
The numbers get even worse if you change the 16 man bracket to an 8 man bracket. Weird numbers (10 man bracket, 2 5 man pools; 12 man bracket, 2 6 man pools etc.) don't have any effect.
You can't dodge the fact that a round robin is way more accurate than a double elimination bracket unless you'd like to propose a different metric for assigning seeds. There's no rule that says you have to try all the time/no strong prevention of rigging atm (it's called, DQ the entire pool that rigs and advance additional members from other random pools, or have judges for the pool) BUT if you don't try that's a risk you're taking on your own.
Even Chibo/GDX/Keitaro etc acknowledge that bracket pools are mainly beneficial due to avoiding sticky tiebreaker situations and timesaving. Has nothing to do with accuracy. BTW there's like 0 problem with time when it comes to Ohio tournaments lol, we have some of the best efficiency in the nation tbh.
You're basing some filler sets on what matchups take place? To that I say: if you don't vary your own options in terms of character choices, then you deserve to lose to those matchups if you ever encounter them. I also now see MK as a godsend against double-blind lameness (something I've used from time to time), being the X-factor choice and all.
Filler sets in bracket are WAY different than filler sets in pools. Filler sets in pools, as you identified in a previous post, are caused by people who have "secured" a seeding position (which is why the best pools have specific play orders, but no one's done that since FC because...I dunno lol). Filler sets in bracket occur because of bracket position and are statistically unavoidable due to the number of single character mains in the Brawl community and the polarized nature of matchups in this game. Calling out people who aren't willing to pick up other characters to stop these filler sets from happening doesn't actually change the fact that they happen anyways; you missed the point lol.
Sure, you get more sets that matter, but that leaves a chance for hype (a huge positive toward growth if you ask me) to get prodded in the bootyhole, especially for higher seed matches that might be sandbagged if one or both players already have a secured spot in the next wave. Plus, since moving to another pool is essentially a reset, that may also further promote sandbagging if there isn't as much of a "fight for your tournament life, you get two chances" factor present. It gives people way too much time to figure out the other player if they meet again (the only notable comparison to that is a player having to win two sets against the other in Grand Finals of a double elim bracket).
I don't see how you came to the conclusions you did in this part of the post. Hype doesn't come from elimination potential lol. Hype comes from the player matchup itself most of the time. It also comes from how close a match is, or how significant a match is (which isn't determined necessarily by format or elimination; see crews or money matches). The only time that higher seed players will get a chance to sandbag, especially at a tournament that is of a sufficient stack level, is the first round pool. "Fight for your life, you get two chances"? "Fight for your life, you can't depend on other people to perform the way you expect them to". Seems roughly equivalent to me, one just requires more thinking than the other. "Way too much time to figure the other player out" is irrelevant in the face of winning lol. If you can't adjust to being "figured out", sucks to suck.
Growth comes from bottom up strategies. This is a bottom up strategy that caters to middle or bottom level players to build their experience. At tournaments that are large enough to warrant brackets (40 or greater) I think Juggleguy's Hybrid Bracket format is the best. LBR2, LBR4, etc. as round robins sound like a great idea to me.