Does it?
There were a boat load of customization options available in Halo (you could create many interesting game types just like PD) and the game play itself had more depth. Plus, you could link together four other systems for 16 player games. I'd say they were both loaded with features, but those features were more usable in Halo.
I mean, try playing a populated botmatch in PD.
Yeah you definitely have to be able to adjust to the framerate in PD. But as far as customization and the resulting variety from that customization, Halo isn't even on the same planet. A big part of that is in the weapons of Perfect Dark and how they change the entire dynamics of each mode. Most of Halo's weapons are more typical FPS weapons, although how they are used with the shield is what gives them some depth I will agree on that aspect. And the vehicles of course as well.
But let's take take a look at some for PD:
Slayer: Rocket launcher with a secondary fire of an endlessly controllable rocket with a camera on it. People will find a hiding spot and peruse the entire level trying not to crash it into walls and finding prey, while hoping they aren't discovered as they are vulnerable while controlling it.
Laptop Gun: Secondary function to attach your own sentry turret anywhere in a level and have it fire automatically at enemies, you can use it to protect yourself in King of the Hill or all sorts of other cool ideas.
Farsight: Can see and shoot through walls across the entire level, secondary fire caused your reticle to slowly hone in on other players so they have to keep moving, although the shooter is vulnerable much like the slayer.
Tranquilizer gun: Can fire at an enemy to blur their vision, the effect slowly wears off.
N-bombs: Bombs that exploded spherically and blur the vision (extremely) of players that get caught in the blast. It can get crazy chaotic with these going off all over the place.
RCP120: Secondary fire makes the user completely invisible but it burns ammo very quickly, and they become visible again when they fire.
Grenade: Secondary fire is Proximity Pinball, which is a grenade that bounces around the level endlessly until it hits a player and explodes
Dragon: Secondary fire has the user throw the gun onto the ground. The gun is set to detonate like a proximity mine while other players think they are getting a weapon pickup.
Disarm: If a player has no weapon they can make a mad dash or sneak up on another player and disarm/punch them, this will blur that players vision and cuase them to drop their weapon which you can pick up and kill them with.
There are a shit load of other weapons and unlockable goldeneye weapons as well, but I think you can see how much the variety of weapons can vary the gameplay in the game.
Assuming you know about Perfect Darks bots which multiply the variety 100 fold with the different personalities, like the peacetSim that tries to disarm all players and hoard all their weapons or the prey sim that goes after the weak or newly spawned. Not to mention you can have bots on your side and give them general instructions.
And then of course in addition to the co op that Halo also has there is Counter Op which I'm sure you've heard of, where one player continues to respawn as one of the generic enemies in the campaign while the other plays through the campaign.
