People keep bringing up policy violations, but when asked you either get "crickets" or the subject slightly changed. The only policy that I could find that might apply would be Fedora Forbidden Items
and if you read it, you'll find that it absolutely does not apply in this situation.
Now, let's be somewhat pragmatic here... you're going to get rid of Firefox (which doesn't violate any Fedora policies) and replace it with exactly what? Konqueror, Web (the browser formally known as Epiphany), Midori, etc.? Really? Does anyone seriously believe that these products would be embraced by our user base? Someone mentioned IceCat earlier... I installed the current version in the Fedora 20 repository and let's just say that it had a few formatting issues and leave it at that. The vast majority of folks are just going to roll their eyes and install Firefox or Google Chrome.