So you seem to know what Loadout means? Is it a pre-game loadout? Is it a credit based loadout (aka Counter Strike)? Is it a station based load out(Tribes)? What can be loaded(armor perms, weapons, etc)? There is a lot unknown, and saying it is class based is stretching it pretty far.
The real comparison to Tribes is mainly in gameplay style and not feature sets. Jetpacks are nothing special, vehicles are nothing special(although, no other game's vehicles control as well as Halo's), etc. It is mainly a hard to place feeling that the combat and mechanics of Halo are similar to Tribes. The mixture of guns, grenades, and vehicles are most likely the candidate with Halo placing an emphasis on melees as well.







