DOES it put a "lot on her shoulders"? Does it really? At a company as large as Facebook, is there ever really so much riding on any particular person in management? I doubt it.
I’m not familiar enough with the higher management, but yes, there are many incredible people to support both. I suspect that when it comes to dealing with parties like high-level political players, or being the public face of the company, they are unique. I'm noticing Lori Goler's name more in the press; that could be an effort to avoid that.
Chris Cox, Boz, Shrep and Jay Parish are all people I wish people knew more about (outside of Hacker News; any regular here not knowing them is a clearly at a loss).