i don't know how much choice obama had about a lot of his policies, particularly with a congress whose main goal seemed to be in gridlock above all else. in spite of that, it sounds like he managed to get some things done.
for example, the pedal-to-the-metal bailouts of the financial markets turned out to be a massive success that not only wound up turning a tidy profit, but arguably prevented a total collapse. that's a pretty big honking deal, if you ask me.
anyway, i think the two biggest mistakes obama made were in 1) spending virtually his entire popularity and cachet on a watered-down healthcare system guaranteed to please almost nobody, and 2) allowing this valerie jarrett woman to dominate his council so completely, from what i've read. seriously... her level of power and access is disturbing, and it seemed to create an 'us against the world' mentality that we had already just suffered through eight years of with bush junior.
i think the big problem with today's presidency is that it's practically a hopeless job. there are a lot of very serious problems around the world that need to be addressed years ago, but the office is not much better than being that of a 'big persuader' from analysis i've read.
IMO the real problem is this-- if citizens have gotten used to living at a certain level of privilege and luxury and refuse to willingly give it up, then the president is barely going to be even a relevant persuader. it will therefore be the lobbies that make congress dance for us by proxy. meanwhile, the earth's resources will continue to be plundered, pollution of various kinds will continue to have a huge impact, and our military and policy-making will be forced to throw its weight around in order to protect our interests across the world.
now we're heading towards a situation in which a monkey with a bad wig will quite possibly be the new ringmaster. that's an even worse outlook, because that's not only the type that will probably get little of note done, but will make additional, unneeded blunders that just make the whole situation worse.