Crucible was originally called "faction wars." Since there were supposed to be 5 factions in the game originally (the 3 we know, plus the seven seraphs and the cult of osiris), the base idea was fighting for your faction. Obviously this idea was scrapped pre-alpha/pre-reboot and now we have the crucible. I like the idea of fighting for a faction in the crucible (halo reach had "rocket hog" with 6 different teams of 2 at one point, so bungie has shown previously that they liked the idea of a lot of teams battling it out), but I doubt they'll do that again anytime soon. Maybe if they ever implement space combat in destiny 2 or destiny 3, we'll get to see a version of ship wars with a bunch of teams, but until they add more of the factions into the game/lore, it'll kinda be a bit weak with just 3 factions fighting. At least with 5 factions, they can say it's friendly combat to see who's the best, and there could be variations to the game modes, but with just the 3 factions, they can only do so much (one match is a 6v6 of dead orbit vs new monarchy, the next could be 4v4v4, but it gets little variation.... throw 5 factions in the mix and the possibility of tournaments and all different sorts of match variations could be thought up). I'd like to see something of a faction war, but it won't happen in destiny 1 or anytime soon (they have mostly all of destiny 2 decided on already, they're just still building the content... maybe a late DLC in destiny 2? But I doubt it cause they don't wanna fall behind with content creation like they did the first 2 years of the game, so maybe when new ideas are implemented in D3).