This was actually addressed in the newer version of the game, Risk 2008 Revised edition, states in the rules: Player 3 receives an additional card Player 4 rec

This was actually addressed in the newer version of the game, Risk 2008 Revised edition, states in the rules: Player 3 receives an additional card Player 4 receives an additional card Player 5 receives two additional cards In the games we play, this usually neutralizes the first players advantage.