About the designs
The initial idea was that the designs would not be specific to a team or sport. We wanted fans to be able to wear the shirt to any stadium or field, regardless of what it was. The shirt would fit in at baseball, lacrosse, arena football, or a Saturday morning soccer game at the park. There are a lot of different fans and a lot of different sports.
Well, I messed up that whole idea with our Beautiful Game shirt. I grew up playing the game, and I still love a kickaround. I had an idea for a simple type treatment and an endline/touchline design, and we just rolled with it. Soccer (yes, I called it soccer) will always hold a special place in my heart, so it was okay to have this one design. Plus, we recently added the MLS to the site.
The other designs are all clean and straightforward. We kept everything on gray and black shirts for the first drop to keep it neutral. A few professional teams have black and gray, but we weren't too worried about that.