I like some of Neo's ideas. Here's mine, only for "evolutions," not expansions:
Pittsburgh is a natural for the Berlin logo.
Philly can go a lame route and borrow the Surge S, maybe in front of a star instead of a triangle. Or, go big with the idea of Stars, with the Galaxy logo.
Orlando could somehow use the Centurions, or rebrand the Mad Dogs logo.
Tampa Bay is among several that can use the Ottawa Renegades, along with Texas and Arizona. The Wranglers could also use the Riders with an Arizona flag.
The Gold sure could use the Gold Miners.
Invaders could use the Claymores sword, maybe make it a lightning bolt sword.
The Knights also could adapt the Centurions or maybe the Claymores.
I wouldn't update Atlanta to the Rhine Fire. I don't think that logo was as good as Birmingham's.