Gamecube Accessories fully compatible with Nintendo Revolution

There is word that all current Gamecube accessories will be compatible with the new Nintendo system. What does that tell you? Although the unit is expected to have wireless controllers right out of the box, there will still be 4 ports for controllers? What about the GBA Player? All of our questions will be answered by the end of the year. Everytime new information is leaked on this system just gets me more and more exciting about the system!