Invasion is popular - that much is obvious. But why not take it a step further?
All gametypes (CTF, Team Slayer, etc.) could have an asymmetric option. That is, each team gets different loadouts and traits. For the sake of balance, teams would swap positions each round.
For example, one team gets camo and swords/snipers, the other gets railguns and overshield. Hilarity ensues.
Of course, there would be a setting where one team plays as Elites, the other team as Spartans. So it could pretty much be Invasion combined with any other gametype.
Is this good, or perhaps an example of too much variety?