Conquest Modes, I truly believe, are the best thing to almost happen to video games. There was a weird, brief time when it looked like they might happen around 2005, seemingly off the back of a wave of appreciation for Total War, when they started popping up in everything from other RTS games to the original Star Wars Battlefront 2. But then - poof! - gone.
I would very much like them to come back. It's taken me a while to realise but conquest modes are often the secret ingredient to some of my most beloved games, home to my most beloved pre-adolescent memories. Not to be confused with the tickets-and-control-points Conquest mode in Battlefield, which is fun but not what I'm on about, the conquest mode I'm talking about is where you get a big, often slightly silly layer over the top of the "actual" game itself, in the form of a map with regions or planets or whatever that you strategize over capturing, and fight over down on the real-time ground itself. A metagame, if we must use that word: a driving, continuous reason to keep playing the game, but essentially one that is also a game itself, as opposed to just a path of XP unlocks or a paid-for pass.
A favourite of mine - if we're excluding Total War, which is sort what you get if you make an entire series of conquest modes, where the mode itself is fleshed-out and maximised to its logical conclusion - is the one that came in the Dawn of War: Dark Crusade expansion, which frankly had no right to be so good. The story here, if you chose the Space Marines, is that you've landed on some xeno planet and just about every other intergalactic race (there are seven of them) just happens to show up as well. If you play as the Necrons, it's a bunch of rowdy neighbours moving in and waking you up. If you're the Tau then apparently you think this planet's yours. Everyone's here, basically. Orks! Imperial Guard! Chaos! More! For some time since, quoting the hyper-committed narrator's "...and then the Eldar came!" has been a running joke with friends.