What I would do different
Since it seems like everyone has one of these threads, here's mine
1. No Auto-aim. At bare minimum dumb it down and make it optional. Cheating should get you body shots, not head shots. And people who'd rather not cheat shouldn't have their aim screwed with. It's irritating.
2. Side content. Racing missions are good step in this direction. It seems like every problem in this game is an issue of pressing the interact key. I'd like something that has the same quality for this as fishing has for mmos. Nothing amazing, just something to do when I don't really feel like concentrating so hard. A mini-game or some mindless simple task that accomplishes some insignificant purpose.
3. Voice over and script improvements. Cass sounds like a bot reading a script... a bad script. Her lack of enthusiasm when using profanity is made infinitely more irritating by the unimaginitive euphemisms for her sleeping with people. If you're going to have her imply that she got info from someone by sleeping with them, you need to do better than "some... friendliness". By avoiding being sexually vulgar while simultaneously avoiding humorous approaches, you fall in to an unsatisfying grey area of terrible writing. Either have the balls to have her say "I had to suck his 2-inch **** for this intel", or have her make a stupid joke about sweater-puppies. I don't care which. Just don't sit on the fence about it. Also, if you have her mention this sort of thing off-handedly and it never comes up again that she slept with so-and-so, that's bad writing on a completely different level. Also, if you decide to go with vulger, you could hire me as a writer, I've got lots of better lines than that... some slightly cleaner... "had to kiss him hard and where it counts"... just do something more creative. Personally, I think she could be much more bitter and cynical.
4. Puzzles. Not all the time, but sometimes, it'd be cool to have a puzzle element to a mission. Even Duke Nukem 3-D had locks that required you to figure out a three-button combo. That's a terrible example, but I think it makes the point clearly. Really, anything to change up the monotony of go here, use interact key, kill some guys, repeat. Maybe even missions that specifically require you to shoot long range or use melee for some reason... Maybe you have to shoot a guy really far away so that you'll be in position for some event that triggers. Maybe those, "go find these pieces of evidence" missions could not mark what you're looking for on map... so you'd actually have to find them your self.
5. Ammo at spawn and home. It's bad enough running out of ammo in a mission. Having finished a mission after running out of ammo is an irritating death trap.
6. Have the map list the "size" of an arkfall in regards to the pursuits.
7. Less random-spawn crap in race paths.
8. Have EGO shut up about how there's a challenge near by, particularly mid-mission.
9. Make more use of ladders.
10. Make sniper shots while cloaked count toward acheivements, even though it technically cuts out when you shoot. Currently, my best tactic for power kills is invisible man with grenades.
11. At some point, explain the controls fully. I still don't know how to roll on xbox.
12. More info about a mod before you buy it. I saw two for the same weapon type with the same stat bonus, just different names.
13. At character creation, less markings that center around the eyes. It seems that almost all of the irathient and paint markings are eye patterns. Not everyone wants to be a harlequin.
14. As you can imagine, I'm just digging for every nit pick at this point, not because I hate the game, but because I want to put it all out there. I don't intend to cancel my pre-order. I just think there are serious improvements that could be made.
15. Also, is there anybody who really wants to admit that they want auto-aim to stay in the game? I seriously don't know where that gaming trend started, but it needs to stop.