This point by David Corn about the differences between the Tampa and Charlotte vibe seems entirely correct to me.
Tampa was an antiseptic affair. The arena was in a security area that resembled a Green Zone. Delegates were bused in, then bused out. With scant interaction between the convention and the rest of the world, no sense of community was created. It was as if the GOP delegates were suburbanites—or exurbanites—commuting to and from their place of business, zipping past the locals and their neighborhoods. In Charlotte, the delegates and others have flooded the downtown area, walking from one event to another, interacting with one another, the residents of the city who have flocked to the city's center, and even the street-corner anti-abortion protesters. There's a vibrancy that embodies the best values of community and urban life.
I find I am seeing and talking to more people in an hour in Charlotte -- including a friend arrived all the way from Kurdistan! -- than in a day in Tampa. Yet the difference seems based as much on the cities as on the parties: despite the far-flung accommodations here in Charlotte (I'm in South Carolina, which seems bad, but the Washington Examiner people were assigned a hotel in what ought to be called West Carolina), the city itself is surprisingly well suited to conventioneering, despite its small size. From the arena in which the speeches are set to the media workspaces in the convention center is an easy walk along real city streets. In Tampa, the equivalent trip took you through an Eraserhead dystopia of underpasses and asphalt plains.