I'm just suggesting that without the stellar graphics, the game wouldn't be the juggernaut that it is.
A short rant @ Graphics & Gameplay
Lets start off with movies as an analogy. If we had a cast with a script, and shot the movie twice, once with no wardrobe or sets and cheapo cameras and the other with a multimillion dollar budget, the end result is basically the same. Same actors and acting quality, same story, and so forth. But the production quality suffers in the former and is a hurdle to the experience and believability by the viewer. So which is the better movie? The one that immerses and conveys the media the best.
The same applies to games. Putting aside technology that actually improves the gameplay noticably, it is true that many games could be done with stick figures and black and white worlds while retaining the same gameplay elements, story, etc. Yet the graphics are more than just something on screen, they are a principal part of the experience, especially artistically as a means to convey emotion and the players role and place in the world.
But there is more to this. Humans like "escaping" into gaming worlds and enjoying them. e.g. I run across a shallow puddle. In the ugly-game the water looks like a blue texture with no visual or auditory recognition that it is water beyond the fact it is a blue texture. In the pretty-game the puddle ripples and splashes a mist around the player, visually soaking the clothes. It is so much fun I go back and hop up and down some to get a kick out of the experience.
It is fun.
The novelty will ware off, but the fun can never be stolen from me. Likewise, as I play the game I get the enjoyment of seeing my targets splash around through puddles, as well as drawing me closer and closer to the world. The ugly-game, well, may have the same mechanics but seeing my enemy run across the blue texture with jerky animation is a jarring experience.
I would also submitt that graphics, even when not functionally a part of overt gameplay mechanics, do add to the gameplay. Cleaner image quality allows for easier recognition of targets and movement. Visual aids to the condition of the environment can help identify the effect of the world condition on your ability to complete tasks. Humans rely strongly on vision, and a vital part of video games is what is put on video screen.
There have been games with average-to-poor graphics that were sensations as well as (unfairly, from a gameplay perspective) duds. Likewise many a crappy game has sold well due to graphics. But I can think of very few games that could be harmed by better graphics, and most of those are classic puzzle games that graphics merely serve a functional purpose.
Graphics is not a substitute for gameplay, but in most cases games are not designed with, "Take resources away from graphics to work on gameplay". True, there will be graphical compromises to reach a gameplay goal (GTA3 is an example) yet even then the tradeoffs can still be graphically pleasing (e.g. trading off NPC detail to allow having multitudes more NPCs).
A game with good graphics and poor gameplay is a poor game. And a game with poor graphics but killer gameplay can be an exceptional game.
But at the end of the day, what separates the juggernauts and the also rans is across the board quality. If Gears of War had worse gameplay (even Lost Planet gameplay) it probably wouldn't be the juggernaut it is today. Did graphics help Gears of War become the game it is today? ABSOLUTELY. But Epic shouldn't have to apologize for that. The graphics make the game more enjoyable and emphasize their gameplay decisions. At the end of the day Gears of War did well for many reasons -- Graphics, Sound, Gameplay Mechanics and Balance, Features, Gore, Hype, Exceptional grass roots marketing, a theme and art style people enjoyed, and so forth.
Would GOW be the juggernaut it is without the graphics? Probably not.
But the same holds true of most "juggernaut" games. Downgrade the graphics of MGS, Halo, FF, and what you have left is a really good game that most likely wouldn't have had the impact it did on the market.
There are always exceptions, but over the last couple console generations the consensus "Top 10" on each platform almost always share things in common: Excellent Gameplay Experience and/or Value, Strong Marketing and Market Placement, and Great Graphics. A game missing any one of these 3 virtues would find it difficult to find itself near the top in critical acclaim & sales.
Sadly, many games have come quite close to jumping from "good" to "great" but failedto issues like lack of finishing polish, minor balance issues, slightly rough content, poorly executed story or acting, lack of market appeal, lack of marketing, etc. What makes the great games great is that they hit a lot of homeruns where it counts. Would Halo be the same success with limited multiplayer? Would FF be the same success with a rougher story? Would Gears be the same success with rougher graphics?
Of course not. At the end of the day the question is the gameplay just as good with worse graphics. And in many games cases, yes. But the next question should be, "Is the experience the same with worse graphics?" Is it as much fun? Do the subtle benefits of the graphics, the sum of its parts, add up enough to improve the experience and the gameplay in minor ways that lesser graphics actually harms the experience?
I agree there have been quite a few games that succeeded based on the merits of the graphics and were hallow shells of a game (look at DK on the N64). But I don't see Gears fitting that category at all.
Ultimately graphics are a significant part of what constitutes a game. At the end of the day it is part of the value and enjoyment. Don't get me wrong, I can play games with trashy graphics, but that doesn't mean better graphics wouldn't improve the experience. And having great graphics can be the difference between a "great" game and a "good" game based solely on the merits that better graphics can contribute to a better user experience, even if they don't directly impact the gameplay. While most of us are mature enough to see that a game can have simple graphics and addictive gameplay is a very good game, but if we were given the choice of the same gameplay with killer graphics we would take the killer graphics edition because we are visual creatures and great visuals draw us even deeper into the game.
Looking at Gears of War we could ask: Putting the visual experience aside for a moment, how do the other parts of the game stock up compared to the market? Innovation and user interface/experience, gameplay mechanics and interactivity, balance, story, features and value?
How one answers those questions will be a mix of subjective points (e.g. I hate the voice acting) and objective (the online modes are broad and solid), and the ultimate worth of those reflecting on whether the game is better than another is to a degree personal opinion. But in regards to sales and consumer desire you pretty much have to take the game as a whole, graphics and all. It is extremely difficult to gauge the markets reaction to a game if it was downgraded in significant areas. And academically irrelevant because the impact of such changes falls completely (in most cases) in the realm of individual interpretation. I can think of a number of games that would have done much worse (or better) with a change in graphics, but then again I have seen games that have little redeeming value (or are a shadow of their reputation) get massive praise and consumer acceptance.
In the end some of the discussion can be interesting (e.g. mechanics), but as for the awards the fact Okami and GOW have won many of the same awards in the same year and one bombed and the other is a huge commercial success tells us these awards are not always a testiment to consumer adoption and that gaming has evolved, good or bad, as a medium where success and failure is a fine line that can be difficult to quantify. Why does another space marine game do and another fail? Why does one game with a dog hero sell exceptionally and another of similar quality and awards not? Gamers are fickle and success can come down to things difficult to tao (culture) as well as things outside the powers of the makers themselves (marketing pushes). Being in touch with the consumer heart beat and dumb luck seem to be as a big of factors as any in regards to the way we valuate the quality of games.
Anyhow, my graphics rant is over. Long live graphics because in 10 years they won't matter!