Darknes is exactly right. In fact, one of those teams is already in the league, though not yet in those cities or under those names.
Crows is alliterative, but I like the nicknames that I have for those two cities more. Based on how the league grew last time, Denver, Buffalo, or Portland would have been likely to pick off the Crows nickname - I liked the names that I had for them, but not the identities (Colorado's white jersey was probably my favorite, but their logo wasn't original enough, and I never landed on a logo that I didn't hate for the other two).