Memphis and New Orleans have a hard time with pro sports (save for the resurgent Saints of the past five years.) Portland is too small and too close to Seattle. Las Vegas would have to have Nevada amend the gaming laws, and they're too close to the Diamondbacks. As for Jacksonville, there's not a great attendance record among Florida teams, even during a play-off series.
You’re kidding right?
Portland too close to Seattle? It would make for a good rivalry!
Are the White Sox too close to the Cubs?
Are the A’s too close to the Giants?
They would also need a $6bil ball park with a roof...as would Las Vegas.
The other locations could go with your run of the mill $2.5-$3.0bil ball park.
Portland being the weakest candidate due to 30 years of conditioning as Mariners fans.