Fantastic feedback, now for some explanations on the placements.
Oblivion was the first RPG I thought of that has little/no shooting in the 1st person. I play a Swordsman most of the time in Oblivion anyway, so I totally forgot about the arrow aspect of the game (heheh... sorry to all the marksman rogues out there). What I was trying to get with Oblivion was the farthest-"left" game in terms of RPG-FPS. I guess a better game would be Fable, the guns in the game never go into 1st person, though a VATS-esque system was implemented in later games, the shooting was never really about how skillful you were with a gun, just how powerful your gun was and how good you are with one, as basic RPG formula dictates.
Fallout 3 & New Vegas are, despite first appearances, RPG's with Shooter elements. In a game like Borderlands, if you're a good shooter, you'll hit all the time with your gun. In Fallout 3, if you put enough points into the Small/Big Guns skill, you'll hit all the time. One is based off numbers, one on personal skill. New Vegas added a more in-depth crafting system that, as an adoring Oblivion-Alchemist, I loved, but the Iron Sights is one of the core aspects of the First-Person Shooter, putting New Vegas more right than its predecessor.
Deus Ex: Human Revolution is an odd one definitely. With a game that has an achievement requiring you killing NO ONE save bosses, it's a definite choice-based RPG. However, the fact that you CAN go through the game playing it like Borderlands pushes it farther right than New Vegas, due to its corridor encounters and even MORE focus on bullets hitting because of skill, not because of numbers (mostly).
Borderlands is a good mix. There's Diablo-esque loot, a 3-tree World of Warcraft-esque talent tree, AND shooting based off of skill. Sure there's a little shaking at first, but if the crosshair's over the enemy, they're getting shot, unlike how the bullets decide to go to Wendy's even if you're aiming DIRECTLY AT THE ENEMY in Fallout 3. It's a near-equal mix, with Iron Sights and an open world to settle the balance.
Bioshock is, again, another odd one. as one so close to the middle, it's not a traditional RPG, but the shooter elements shine like gold. The shooting is solid, you can (finally) carry more than two guns, and upgrade your character with a variety of plasmids and gene tonics to change your playstyle to your own specifications. It lacks XP and leveling though, and while the "Mana bar" does push it left, all the shooting elements keep it on the far-right.
RAGE is a game I haven't played yet, but have heard quite a bit about. It may/may not move left on the MY personal list, but since its a game developed by id, the father of the FPS, I just assumed it would be farther right. I'll play soon and update the chart accordingly.
Call of Duty 4: Modern Warfare's campaign is, yes, traditional shooter fare. However, tell me where you've heard of this before. Gaining XP based off of kills, leveling up, acquiring new weapons, editing your arsenal to how you want to approach a conflict, and changing about your passive abilities for your character. I just described two games. The recent RPG-Indie hit Bastion, and the 3rd 2007 FPS Juggernaut, the Call of Duty 4 Multiplayer. I probably just blew your mind. That's right CoD Multiplayer fanboys, you're in love with an RPG.
I've already mentioned The Darkness, but I forgot to put a far-right extreme FPS from this generation, as this is the generation that seems to be really embracing the FPS-RPG mix. The first one I can think of is Halo: Reach, but even that's a little left due to the leveling-up for cosmetics system. I'm guessing the best we have right now is... hm. I'm a little stumped now. GOT IT! (I was sitting for a full two minutes thinking) Half Life 2: Episode 2.
Yea... the third episode in a game from last generation...
It seems as if the FPS is really embracing the RPG, but seriously, if there's a game from this generation of games that's a true-blue FPS from the far-right, please make notice of it! (I think that new game "Hard Reset" is, but I'm not sure)
Oh, and I'm sorry about only staying within this generation of games, I only recently started really getting into Games, and I'm a bit fuzzy on stuff before 2004. Sorry, but I try my best 8^D
-Chillz