Nobel Peace Prize laureates are usually taking a stand on controversial topics in their own countries/communities. They need an international prestigious stamp to show that they are on the right side of history and have international support. But also you need to deserve it. Malala has the perfect balance of both. She is incredibly smart, self-conscious, has a natural sense of dignitiy and integrity that protect her from the traps of ego and fame - something very hard to do for any human being, let alone a teenager. She is making quite an impact on girl's education. But also she needs it badly. Her life is constantly in danger and this stamp and support from the Nobel Prize will protect her life and her struggle. More people in her community will consider that she might be right.
Red Cross is another example of both deserving and needing the prize. They must enter the worst war zones, and all sides must believe they are not spies for the enemy. Their brand is the most important brand in the world.
Then you have Obama. His prize is controversial because he obviously didn't deserve it. But the commitee thought he needded it, and I agree. Not because he needed more power or validation, like Malala. But he could use a "nudge" to improve peace in the world. Sure, it was a risky move - and didn't pay well. But it is part of the goal of Nobel Peace Prize as I see it: help the laureates to do the right thing toward peace. So I don't think it was a necessarily bad move. But it surely hurts its brand. I think the commitee should be more conservative about who deserves its prize; but I agree that is also important to find who need it.