Fig
The Altruist
As much as I like Ghirahim, I always had my doubts if he would be a playable character. But to replace Ganondorf? I don't see that happening, maybe Demise, but not Ghirahim. Ganondorf is such an iconic character that I doubt he would be replaced by someone who wasn't as popular, let alone appeared in only one Zelda game so far. Ghirahim would make a great addition to the Smash Bros. roster, but I just don't see that happening now as we get closer to the release of the 3DS version of Smash 4. If anything, I see Ghirahim as either an assist trophy or a collective trophy and this thought is due to how there are not that many references to the Skyward Sword in Smash 4 other than the Skyloft stage. But you never know what is in store for us, so who knows? But personally, I don't think Ghirahim will be a playable character in Smash 4.