I believe that my system is the best. Here is how it works:
Halo 5's RNG (req pack) unlock system for armor, assassinations, skins, etc annoyed many people who prefer to earn their cosmetic items through methods such as ranking up and/or completing achievements. Therefore, for Halo 6, I propose the following unlock system:
With the exception of Warzone exclusive items (loadout weapons, power weapons, vehicles, etc) which will be still obtained in req packs (using req points not money), once an cosmetic item is unlocked it will have to be purchased using req points (kind of like Halo Reach's system but with req points replacing credits).
Armor: Armor in Halo 6 would be unlocked in sets through ranking up (through Spartan Rank). These sets would include the helmet, shoulders, chest, forearms, and legs (which can later be mixed and matched with other sets in the armory).
Visors: Visors will be unlocked through ranking up as well.
Weapon Skins: Weapon skins will be unlocked by completing certain milestones pertaining to the specific weapon. For example, in order to unlock a certain skin for the Battle Rifle you would need to get X amount of kills, headshots, or perfect kills with the BR.
Assassination Animations: Assassination animations would be unlocked by getting a certain amount of assassinations and/or beatdowns (for those of you who just want the kill).
Stances: Stances would be unlocked by completing certain achievements such as beating the campaign on legendary.
Thruster Effects: Thruster effects (similar to armor effects but limited to the thruster animation) would be unlocked by winning a certain amount of multiplayer games (both arena and warzone).
Emblems: Emblems would be unlocked from the start as in earlier Halo games.
Warzone Unlocks: All Warzone unlocks, including permanent unlocks (loadouts and armor mods) and one time unlocks (power ups, power weapons and vehicles) would still be acquisitioned through a RNG requisition pack system (as in Halo 5). Req packs would be purchased using the same req points one uses to purchase unlocked cosmetics.
Req points will be tied to xp points, meaning that if a player gets 100 xp after a game they will get 100 req points. The exception to this rule would be if a req boost was used, in which case the values would differ based on the boost’s multiplier. With a 1.5x boost, for example, a player could get 100 xp and 150 req points. More on req boosts later.
Req and xp points would be obtained from playing matches of multiplayer, customs, forge, campaign, or any other mode. Like in Reach, players will earn points throughout the match based on their performance with additional xp and req points being awarded after the game as well. Completing a campaign level, for example, would give you points based on the difficulty you played on. Completing multiplayer games would obviously give points too (xp and req point bonuses would be given to players who join in progress or loose players on their team). Forge and Customs would yield marginal amounts of points as well.
Req boosts (giving players more req points per game for a day) would be sold in the req store for real money in place of traditional req pack microtransactions. This way players would have to earn their unlocks, no matter how much they paid. This would also encourage payers to play more during the days they buy boosts as well. There could be different boosts offering players 1.5x, 2x, or 2.5x the req points, each priced according to their value. Note: There would be no xp boosts so that all players are on a equal playing field when it comes to their Spartan rank. Boosts would no longer be in req packs either.
So that's my idea and I think it is near perfect. Put your questions regarding my system in the comments and I'll gladly address them.