I went to a few Rays games last year for the first time. Tropicana Field was not as bad as it looks on TV, but it's pretty bad... The Rays have been trying to get a new stadium for years and they surely need one. But even more important is the team's current location: St. Petersburg is a great town, but the only way in from the mainland to the west and south is across a handful of bridges/causeways over the bay that are traffic nightmares during rush hour (that is, during the time fans would need to get from Tampa to the Trop for an evening game). The Tampa/St. Pete metro area has just over 3 million people, but most of those are on the wrong side of the bridges from the Rays. Plus, a stadium built on the Tampa side potentially draws from a portion of another 2.5 million people in the Orlando metro who might drive to Tampa for a game, but not to St. Pete.
It's a shame--the Rays have an exciting young team and are fun to watch. But the Yankees and Red Sox are juggernauts and geography is working against the Rays. Efforts to build a new stadium in Tampa seem to be dead again (they resurface every few years). The area around the Trop is booming and would be great for a combo stadium-entertainment district like the new Braves facility--but the transportation issues will remain.