4. Proper bosses

There are bosses in Army of Two, but they only just scrape that title. The majority simply require you to get your partner to take the aggro, while you head behind and shoot him them in the back. It's hardly brain taxing and by the end of the game it became a little bit tiresome. The one big boss that you do encounter doesn't put up much of a fight either. Army of Two has a great aggro system, but it needs to do more with it. Unique bosses that require some thought to take down would be a great step towards that.

3. Improved team-mate control

You're not always going to be playing with a real life buddy, so some changes to the AI team-mate control would really help smooth out the single-player experience. You can get by with just follow, head-on and hold firm, but the game's crying out for a Rainbow Six Vegas style point and move command system. Just being able to set up your team-mate in the exact position you want would do wonders for the single-player game.