Here's how I see it. There's Wonderful 101 on one side, and there's God Hand on the other.
One game is about 15 hours, with a large of variety of things you do that isn't combat. There's story sequences, set pieces, minigames, punch-out bosses, a steady stream of new teammates, puzzles, gamepad segments, the whole 9 yards. Now a bunch of people dont like that, they just want to get to the combat parts, say its too long, too much filler, whatever. I fuckin' loved it. Its one of the best games Ive ever played, and that variety, even if they arent all pitched at the same level of intensity, came me compelled to play it.
Then there's God Hand. God Hand is a straight up beat'em'up game, but instead of being a hour long its like 12. 12 hours of running forward to fight the next wave of bad guys. Yes, there is variety in your combat options. Yes, there is a high amount of skill involved. Yes, it feels good to win. But its incredibly repetitive, and unlike the games back in the day that its clearly based on, its about 10x as long to beat. Thats 10x as many waves of enemies to fight, with no real variation in game ideas or sequences outside a couple sparse "platforming" sequences or that one puzzle like 3/4ths of the way in. So as good and challenging and varied as the combat is, if you're gonna be 12 hours long, you need to do something else besides endless combat sequences.
And that's how I see UC4 vs Doom. One game has a variety of things it ask the player to do over the course its 12 hours, and maybe they're not all super adrenaline pumping, but they all work in unison to create a varied compelling experience. Like a balanced varied diet! Doom doesn't ask that, its like eating your favorite meal over and over again 3x a day, every day. Yeah, its a great meal...but I dont want to eat it every fuckin day.
fake edit: for my taste, the game would be more replayable if it was much shorter. So by the end of the game, I want to experience it again, instead of feeling like "OK, I think I've had my fill of this for like, ever, now"