Good point, on the surface the big world problems seem more straight forward because they're technically less complex. But they are much more than technical problems. Social, geopolitical etc...
You're right, though. Sourcing clean water & good food for everyone would be more important achievements. Investing in people brings cascading rewards as the people helped are better able to do themselves good and do good for others.
I think the difficulty of such problems is what frustrates me about them. If asked me to build a whole new computer operating system there are 100s of books I could turn to to get me started. When it comes to these big social issues, I don't even know where to begin.
