I have done some research on this; comparing halo 1's melee with halo 2's. This is what i found.
Halo 1:
In halo 1, all weapons do the same amount of melee damage.
Standing melee: 3 to kill
Moving into apponents melee: 2 to kill
Jumping down onto apponent: 2 to kill, but more power is taken each time
Halo 2:
In halo 2 all weapons do the same amount of melee damage except the rocket launcher.
Standing melee: 5 to kill
Moving into apponent: 3 to kill
Jumping down onto apponent: 3 to kill, but more power is taken each time
Rocket launcher standing: 3 to kill
Rocket launcher moving into apponent: 2 to kill
Rocket launcher jumping down onto apponent: 1 to kill.
I have used one of the halo 2 editors and reconfigured the melee attack in halo 2 to match that of halo 1's, both in mp and campaign. It works perfectly. So when i host all have this increased melee damage.
Having the halo 1 melee damage in halo 2 really make the game more balance for close range combat, especially for those, like myself, who do not duel wield much.
It would sure be nice if Bungie noticed this and is fixing it. Because as is, melee is almost worthless.