This really isn't a big problem for Move. Not too many games on the Wii that use both a Wii Remote and Nunchuck even offer 4 player multiplayer. Even among those games that do though there are games like Mario Kart Wii and Super Smash Bros. Brawl that have such a mode and give the option of using a Remote Nunchuck combo, but nobody would choose to play with that control scheme over a traditional controller or a sub-peripheral such as the Wii Wheel.
For Kinect on the other hand, it's a rather large blow that it seems to be limited to 2 players simultaniously. It's true this wasn't much a problem for the PS2 (multitap aside) but for a device that's specifically designed for casual games and labeled as the future of entertainment to only be on par with a last generation console doesn't bode too well for it.
