Be honest. It really doesn't matter how much experience he has because this is America. He could be the most qualified on either side, and if he did get the nomination, in the general election, there is a percentage of Americans that simply will not vote for him for an obvious reason.
The same could be said for Hillary. A certain percentage of the population will never vote a woman into the top office in the nation. But if someone who had no qualms about putting a woman or black person into office, chose not to vote for them in the primary ONLY because they thought others might be too prejudiced to vote for them... that to me would be sad and pathetic.
I don't have any qualms about Obama in the foreign diplomacy department. He spent years of his childhood overseas, travelled extensively and was raised by a man who lived a majority of his life in Kenya. Obama has an innate awareness of the world, and their perception of us. He is aware of culture and perception differences that many people are not.
Being aware of the impact of how seemingly teeny tiny things appear in different cultures can make a TREMENDOUS difference in diplomatic issues. Back when my major was International Relations we studied some of this with various politicians and the best diplomats were ones with cultural sensitivity (not that they didn't make demands and get their point across but that they did it in a way respectful to the person hearing it). Ie, there is a thin line between drawing a line in the sand, or making a threat wrapped in a demeaning insult akin to slapping the person in the face (the current POTUS doesn't know where that thin line is, Obama I believe would).
Yes, this is different than diplomacy experience, but it still puts him lightyears ahead of the current POTUS... who had neither the background of international and vastly different culture experiences OR diplomacy experience (aside from Mexico).
To me Obama is a breath of fresh air, and Hillary is the same old. I completely supported President Bill Clinton, but I think the country needs new leadership to rescue us from this mess we are in now, and I think Obama is the man for the job.... whether Oprah says so or not.