Seems like a really bad decision by them,
complicated as Frostbite 2.0 might be to use, i expect "modders" would be able to overcome the learning curve and make some amazing things with them.
I also expect "modders" to create awsome content with UDK and the Cryengine SDK in the future, i myself love playing with UDK, and hope to release some stuff with it down the line.