They definitely need to branch out if they want to escape the shooter-centric, bro-fest generalization.
Part of why I'm a Sony fan is because I like variety in gaming. It's not the most lucrative approach, certainly, when you measure sales for individual titles, but I do think it leads to better global sales and, ultimately, more consoles sold.
Having said that, I will admit that such a strategy might backfire, however. A large part of the Xbox demographic IS the Halo/Gears/CoD player who doesn't stray that far from those titles or titles like them. Investing in a Little Big Planet or a Donkey Kong Country type game might not see acceptable returns.
Still, you'd think that there would be room for experimentation. Nothing wrong with trying something different at the start of a generation to see if it sticks. Personally, I'd say they need something with a fantasy setting, to offset the aliens-and-guns vibe. That would be one way to get my interest. It could even be something gritty, like The Witcher, which I think would go over well.
Being practical, they probably need something to replace Gears. Rather than another cover shooter, though, perhaps something with stealth elements and a bit more tactical gameplay? I think the Xbox fanbase would also respond well to that.
