For CTI, I think it would be great to see a Respawn system where you can only come in as reinforcements at the HQ, and only after a Medic has "come in contact" with you. This would make a Paramedic squad viable, flying around the giant island. If you had a squadmate die, you would want to get his body out of there, or protect it until the chopper came.
I'm sure some of you smarter people can flesh this idea out, but I really think it would add a lot to the CTI concept.