Co-op Mode

[Ellz]

I think it would work well. Player 1 assumes control of Phelps, whereas Player 2 controls his partner.
The player as Phelps has control in questioning, but his partner could help by suggesting (or voting) for answers.
Crimescenes can see both players looking for clues.
Chase scenes could see player 2 attempting to cut-off the suspect.
Shoot-outs would simply see player 2 taking control of the normally cavalier AI.

Voice chat would be vital for it all to work of course.

Just a suggestion.

[Big Boss]

Sounds great but I don't think Rockstar games will add anything into that game already. Its been almost 2 years.. But great idea! I'd vote for it :)

[shadow milhouse]

The closest thing we have now is getting 7 of your friends, putting you and one other on a team, and have cool shootouts, and pretending to interoggate them :P

[Anlon]

it would be nice but hard to make

[Tycoon]

I love the idea. It clould be kept simple at the start, 2 players can (at any moment - Look at "The first templar") change who they control, Phelps or any of the partners.