:::HD =/= Realistic:::First off, I believe making a game realistic doesn't mean it has to have realistic graphics. WiiSports Bowling is a perfect example of that. So the HD debate goes out the window. Still, I'd like to say that making the game realistically intuitive doesn't mean it has to be a waggle fest either.
I don't know about you, but GoldenEye: License to Kill: Pistols is still one of my favorite ways to play a FPS. I like the fact that it was fast, sharp, and fun. When it's easy to die, you are more worried about dieing. I know it sounds simple, but it's true. There's a sort of anxiety and adrenal that I felt playing that game, that I haven't felt in a long time. Why is that?
:::Realism stems from realistic behavior:::A realistic game needs a realistic "game world", realistic collision detection as well as physics, animation, and AI. Graphics are the least important part. Imagine a game that took into account where you were shot. If you were shot in the leg, you would limp. If you were shot in the arm, you couldn't hold an assault rifle. If you were shot in the torso, it would slow your agility and speed. Games these days call themselves realistic, but really only have realistic graphics and weapons. There are facets of the game that need to be rethought with at least the same effort developers put into HD graphics.

Notice how the player has been shot in the left leg
:::Player-controlled-context sensitive buttons opens up restrictive gameplay:::I believe the Wii is the only console that can benefit greatly from what I call "context sensitive control schemes." Similar to RE4 with it's ability to change it's control scheme from moving to shooting with a simple button-hold, I think the Wii can use multiple context sensitive schemes to expand the over-arching control scheme and do away with inventive but ultimately annoyingly inaccurate "waggle" control (ie pushing the remote forward to zoom in). Instead, zooming can work like this: when holding the "A" button, which brings up your scope, the "C" button, normally used for jumping, is now used in conjunction with the analog stick to zoom in and out. You hold the "C" button down as you move the joystick back and forth to adjust the zoom. Needless to say, you'll be holding two buttons, interacting with the joystick, and pressing a third button when your ready to fire. While that may sound complicated, the Wii controller is makes it easy due to the nature of the controller being disjointed.

Now that's just one example of changing a button's action in coordination with another.
This setup would finally put to rest any claims that the wiimote needs more buttons. That said, I'm not promoting the idea that every button needs 8 different functions. Instead, I'd like to think that the button (joystick, etc) would intuitively change to the appropriate action if you were to play in that certain context of a game for the entire game.... I hope I didn't lose you.... What I'm saying is: if I were to play the entire game through a scope of a rifle, wouldn't I want a fast and responsive zoom? If you break down a game into its parts and look at one specific part as though it were the entire game, you'll find that the easiest and most proficient control scheme for that part wouldn't coincide well with those from other parts of the game. So while jumping maybe necessary and deserving of its own button for the running and gunning portion of the game; when looking through a scope, you realize that the ability to manage your zoom is far more important. And that's exactly how the compliment is made.
(NOTE: The "C" button can also have another ability, one that's also context sensitive. Since it is used to jump, it would make sense for the game to prompt context sensitive commands that pertain to jumping: such as, jumping out of windows, or jump fences, and/or sliding down staircase rails)
:::Evasion is just as important as attacking:::Another example of modern day games not being realistic is evasion. There are so many times in other games that I wish I could evade quicker but instead I have to try to run away and hide. It's because of this most games boil down to who sees the other person first. Dodging really is still a new facet of gameplay that has yet to be explored in a FPS, especially the dive roll. GOW used diving extensively, and I think they did it well; however, GOW gameplay still lacks in quality. The dive roll would work simply by pressing the "Z" button (which normally makes you crouch) while the analog stick is pushed fully towards one side. Also, when running (performed by double tapping forward) or jumping, pressing the "Z" button will make you dive. The view would switch briefly from FP to TP; returning to FP after about a second. You can even dive into people to knock them down. Diving into them from behind or in front could activate another context where you could bludgeon them. These are just a bunch of ideas, but I really think there needs to be a defensive evasive maneuver. The important thing about this maneuver is the fact that your aim is still independent from your movements. So while you maybe diving all over the place with your view switching back and forth, you can always rely on your aim to still be fixated on that persons head.
Another unexplored tactic is sliding. When running, if you press and hold the "Z" button, you will first initiate a running dive that will be followed by an on the back slide (if the ground permits). Sliding allows you to shoot or melee your enemy's while still fast-moving and low to the floor. And based on what type of ground your are sliding on, your slides can be as short as 2 meters (smooth cement) or can go on forever (sliding down a snow hill). This is more of an offensive maneuver.
These tactics will finally help put an end to stiff FPS's, where the only way to dodge is to strafe side to side or jump. Dodging will allow the player to experience far fewer deaths (especially poorly deserved deaths) and ultimately make the game more satisfying to play. If people are harder to kill, then it'll be more rewarding when you do kill a player.
:::The switch between different views lends itself to the most effective gameplay:::One thing that Halo 3 does well (oh god, bear with me) is changing back and forth from FP to TP view. The Wii has capitalized on that switch before (Prime 3), but in this case it could be the frame MotionPlus support needs. Along side the normal weapons your character can hold is a melee weapon. Unsheathing the weapon (NOTE: by pressing a button different than the weapon-cycle button), be it a sword or pipe or whatever, moves the view from FP to over-the-shoulder TP to help the player better determine how far their reach extends ultimately making it easier to hit that unsuspecting enemy. To swing, you need to first hold "A" down (which locks the view), then replicate the motion one to one. The melee weapon can even be thrown simply by pressing "B" after holding down "A". (NOTE: Pressing "B" or fire when not holding down "A" first will instantly transfer you back to "gun-mode")

What's interesting is in this mode one could add a lock-on feature. If you happen to be aiming at someone, holding down "A" would not only allow you the freedom to perform 1 to 1 motions, but also let you strafe around the person you were aiming at.
The only problem with this idea, is how well aiming and turning in third person works.
:::Overall, fast, competitive, smart, versatile gameplay is the most important aspects of the FPS:::With this setup, you can have a very realistic FPS that focuses on agility, sharp aim, and strategy.
Imagine a game that had no HUD except for a small ammo count and a transparent outline of a body that shows exactly where you are hurting; a game that focuses on managing your weaponry and ammo, instead of simply running and gunning; a game that focuses on disabling and sharp shooting, rather than spraying and hoping; a game where you can dive out of harms way, regroup, and exchange shots; a game where a pistol is actually a worthy gun; a game where your missions are clearly laid out, but not spoon-fed during the actual campaign.
Now, the FPS genre has come along in some respect. For instance, I like the fact that there is an auto-heal if you can manage to duck out of harms way. What I hate is the fact that it's unlimited. Running away when being shot too many times isn't a bad idea, but coming back out to fight as if nothing happened is annoying. And what's worse is that you can still shoot while your healing.
Instead, I think a compromise needs to made. Imagine being shot so bad that you barely make it out of harms way. You can heal yourself by way of morphine shot, but you only have so much morphine. You'll have to re-up to be able to continually heal your wounds. Plus, while you heal, you'll literally see yourself stick a needle into your arm; so no more shooting while you heal. This way people can't just run away as they wait to heal. Also, it'll make health an issue once again. Maybe you don't want to use your last morphine shot even though your arm was shot. Maybe you can survive until more morphine is available.
Anyway, I think that there needs to be more thought put in to FPS's and not just in the way of graphics, but rather fun and inventive gameplay with strategy and cleverness at its heart. That's where you'll get the adrenaline and the rush.
Your thoughts?