I would say in an appropriate game between competiteve teams, a three goal differential in the final score would be reasonable. Four or more goal differential, it is likely a mismatch of teams, of course there are exceptions, every team has a good day and a bad day. Let's say a team wins all three games in pool play by 3 goals, or loses all three by 3 goals. The GD result would be +9 or -9 respectively. A bracket pool where all of the teams GD falls in to a +9 to -9 range is a competitive appropriate bracket. If a team's GD hits the double digits, +/-10, it is highly likely they or other teams in the pool were not properly seeded. I'll definitely do a hindsight comparison analysis with the actual GD results added.
Expected results of misseeded brackets:
Bracket 1: West Coast FC GA and Eastside FC ECNL end pool play with -10 GD or worse.
Bracket 2: Utah Royals AZ ECNL, Pataedores ECNL, LA Breakers ECNL end pool play with +10 GD or better; at least two of these three end up in the Semi-Finals. Bay Area Surf ECRL, SDSC Surf GA, Fram SC GA end pool play -10 GD or worse.
Bracket 3: Beach ECRL, Slammers ECRL, Legends E64 end pool play with +10 GD or better; at least two of the three make it to Semi's. Beach makes Finals, probably wins the Bracket. Rebels IE Brown, Northwest Elite FC ECNL, Pleasanton Rage ECNL, end pool play -10 GD or worse.
Bracket 4: Sharks ECRL, Future FC NPL, end pool play with +10 GD; both make it to Semi's, likely both Finalists. Sacramento United GA, Los Gatos United I, Seattle Celtic DPL end with -10 GD or worse.
Bracket 5: Legends ECRL, South Valley Surf E64 end pool play +10 GD or better. Legends ECRL wins the Bracket.
Bracket 6: Empire Surf Academy NPL wins the Bracket.