You could implement an intuitive cover system. Check whether a wall is in front of the player. If there is a wall and he's moving towards it, switch to cover mode. Pressing the backwards key will let him move out of cover. It is the same like with other cover systems, just changes the triggering event from key-press to just moving against a wall.
EDIT: just checked the net for intense third person shooters...
Look at this, Crysis in third person view, doesn't look
less intense.
http://www.youtube.com/watch?v=aSu7GqL5ovo
that's not the point here, as stated in the first post, this isn't about what looks great, or looks intense, we all know third person shooters look more action packed than fps's(feel free to question that) HOWEVER, i'm talking about the feel that's lost when pulling the cam back, the player is less a part of the game and its now more like he's on the outside looking in, also the cam in a third person shooter alone helps the player because he can see more objects around in unlike in an fps where the player spins the cam 180 degrees searching for a bad guy that's just to his left, we're talking about getting the immersion back and am sure that immersion is lost even from the video seen, it looks fun and intense but the "immersion" isn't the same... once again, anyone should feel free to question this ...
the cover system seems interesting and I'll be testing to see how it works and what are the other downfalls other than the ones that i know directly, including the fact that the gameplay would have to be slowed down but its something i'm willing to do, feel free to make more points on this...
@esper: exactly, dead space kept the immersion high because they lowered the pace of the game, that in itself changes the game from run and gun to where the player has to play more careful then they mix it up with quality sound effects and eerie music and they have their immersion back...
once again, feel free to question any of these points as this is the point of the thread also, other ideas for intuitive cover systems that dont break the flow of the game could be helpful...