Set it in a partly open world
Mirror's Edge stars Faith, a courier who delivers physical documents between people who don't want their communications monitored by the totalitarian government. It was disappointing to play the game and then find that experience instantly take a backseat to a short, scripted singleplayer story.
Bring Faith back and let players experience her life properly in Mirror's Edge 2. Set sections of it in an open world of shimmering skyscrapers, and challenge players to plot their own routes across a landscape of rooftops and vertiginous drops to deliver messages as part of the game's story.
But only sections of it should be open, like hub worlds that connect more constrained missions. Mirror's Edge offered plenty in its scripted areas that's worth bringing back, like the puzzle-platforming atriums that challenged you to scale the innards of some enormous structure.
Add destructible buildings
Freerunning is about gaining a sense of ownership over an environment by traversing it in unexpected ways. (Sometimes it's about running along a small wall while your audience waits for you to reach the next impressive bit). The first game did a great job of that when you were up on the city's rooftops, and a less good job of it when you were inside, trying to quickly maneuver through office space.
How do you build on those ideas, avoid the frustration of coming to a standing-stop when the player makes a mistake, progress the story, and utilise EA DICE's available technology?
By mixing the crashes of Burnout with the military tactics of the Israeli military, obviously.
From this excellent post on BLDGBLOG about Die Hard: the Israeli military navigated an urban conflict zone by moving within buildings, to avoid being hit by snipers or artillery. They "moved horizontally through party walls, and vertically through holes blasted in ceilings and floors," like "a worm that eats its way forward, emerging at points and then disappearing."
One of Mirror's Edge's greatest joys was shoulder-barging your way through a door without breaking stride. What better way to express Faith's fight against an always-watching regime than by expanding that with a limited-charge wall-charge ability using Battlefield 4's destructible wall tech? You'd be a tank doing parkour. You'd be the Hulk. You'd be Ant & Dec.
Make it a stealth game
Mirror's Edge's combat was certainly interesting. It was based around close-combat melee. You could only get guns by stealing them from the hands of an enemy. They significantly limited your speed and agility, and when they ran out of ammo, your only option was to toss them on the ground.
Where it fell down was when it mixed that combat with areas where you were trying to parkour your way out: you'd be looking around for your next jump and people would be yelling and shooting at you. Worse, you'd fail at a jump, experience the frustration of losing your momentum, only to have that frustration compounded by being killed.
There needs to be a greater distinction between parkour sections and combat areas. And combat areas need to be thought of as stealth areas, where attacking is a last resort, and happens only after the player has had the opportunity to plan a swift and silent takedown.
I don't think it's feasible to lose guns entirely, but I do think you can turn Faith into Batman: everyone else uses weapons, but she prefers to climb high above and leap down upon their heads.
Don't change too much, please
Mirror's Edge didn't sell as well as EA hoped, which is why five years have elapsed since the original game. I don't care. Mirror's Edge is one of the most interesting and brave games of the past ten years. There are reasons why people have been calling for a sequel all this time. There are reasons why it's the first game I install on every new PC. There are reasons why even its flaws only serve to make its fans more protective of it.
Like so many games, Mirror's Edge is set in a dystopian city, but one that on its surface appears creepily, almost perfectly clean, instead of one that's crumbling into dirt. That's refreshing, and it makes for a world that I want to return to again and again. Let me.
Secondly, Mirror's Edge is about agility and movement and feeling connected with the environment, and its first-person perspective is integral to that. It has its problems, so add a third-person option. Do not make third-person the only option.
Finally, Faith's fumbling with weapons was refreshing. Tossing away a shotgun instead of reloading it felt cool. Yes, the combat needs changing, but the fix isn't to turn her into Dead-Eye Duck.
The truth is, for everything I want to be different in Mirror's Edge 2 - assuming it even exists - I would be happy if they changed nothing, and simply gave me new, quiet rooftops to run across in the sun.
Got your own thoughts? Drop them in the comments.