I think you guys should give Miami a fair shake with this.
The community here has blown up since 2005. Soccer is very popular now, with tons of places to play 5-a-side including Brickell(near the Heat stadium) lots of leagues people are in.... Brazil vs. Honduras set the record at Sun-Life that was previously held by Barca vs. Guadalajara. I personally have been to the majority of all matches that have happened in South Florida since 2009, Gold Cup, USMNT friendly, USWNT friendly, Colombia Mexico, the International Champions Cup this year... All of which had good attendance.
The NASL team has alright attendance, I could have done better but I'm south of South Beach and that team plays in Ft. Lauderdale.
Beckham I think for the most part knows what he's doing, tons of footballers have condos in Miami already, good investors, big names...
Also there has been an influx of EPL fans, with tons of pubs doing watch parties for big games, same with USMNT games.