Policy-wise, I think the closest analogue to Obama among recent (as in, 20th century) Democratic presidents might be JFK.  People don't draw that analogy very frequently due to the way JFK's term ended, but I think it's fairly apt.  You have a young president that lefties really buy into due to his "hope and change" message, but when he gets into office he's as or more aggressive than the Republicans on foreign policy (remember Bay of Pigs?  escalating involvement in Vietnam?), and while he does pass or try to pass some key parts of a liberal agenda, for the most part he actually governs pretty conservatively relative to expectations.  The big difference being that JFK was elected and governed during perhaps the zenith of America's worldwide economic dominance, while Obama is perhaps dealing with the beginning of the end of our centrality to the world economy.  On any measure other than the economy (and I think it's fair to say that in both JFK's case and Obama's case, outside forces have dictated economic conditions more than anything either president did), I think you'd have to say that Obama has been more successful than JFK...but when unemployment is hovering around 9%, it's hard to see that.

Allons-y!

"Far fewer pundits fault Obama's foreign policy"

That tells you something about the views and nature of the pundit class, and nothing else.

"Will democracy bring "moderate Islamism" to power"

Egypt and Libya's new dictators are less moderate and more Islamist.

Will Arab Spring revolutions be seen as resulting from Bush policies, Obama policies, or Bush/Obama policies?

I have to say, it seems to me the Arab Spring happened DESPITE Bush/Obama policies. The Bush foreign policies that Obama continued were very effective in undermining the prestige of western democracies (Western democracies torture too!), but the Arab Spring revolutionaries went for a change towards democracy despite that.
One reason why islamic parties feature so strongly now after having played no role in the initial revolutions may be that the US made sure that western democracies are seen as having no moral advantage whatsoever. When you have lived all your life under the arbitrariness of a dictator, and you see that the common alternative has no moral high ground, but comes across as just another occupying power after a countries' ressources that will assassinate people, abduct people, hold them indefinitely without trial and torture them - well, then you look for someone who might have a higher moral standard. It may seem comical to us to seek that with the islamists, who to us look like huge bigots and murderers, but I believe to the common man on the Arab street that looks different.