As I said years ago, Bush could be a great president in 3 ways:
1) Successfully war in Iraq.
2) global fund in regards to Africa
3) And manned mission to the Moon

So Bush mostly did #1- at least 90% done.
You say Bush did about 1/2 in regards to Africa
And with the Moon about 1/4 what of needed to be
done in order to count it as something one could count
as great accomplishment.
Though probably one of great things Bush managed to do
was prevent another terrorist attack on the US. [At the time
I didn't think such a thing was "doable"- and of course, luck
may have played a role in this].

But the question is what could Obama do in order to be
seen as a great president, rather than merely being notable
because of the color of his skin.

It seems that the easiest thing would be to strengthen the current
effort in Africa- and thereby mostly "finish it".
The moon seems less likely and probably the best in that regard
in next 4 years could be get it 1/2 done- and that require much more than
continuing the status quo. And doing this is largely dependent upon the Congress and it's funding.

As far as other things. Obviously opening up relations with Iran would important, but it will probably be seen as mostly a result the US involvement with Iraq, so I don't think it would seen as a great achievement as much as a reasonable consequence.

Afghanistan is a quagmire- and I have always said it will take longer than Iraq. Our involvement needs to continue, but probably some break through needs to be reached between Pakistan and India in order to any significant progress. Though if we achieve a good relationship with Iran that could a path leading to more success- but that is not as likely. Having that kind of relationship requires much more than simply opening relations.

N Korea is mostly a problem involving China. Sudan- again China- though not as dependent.

But anyhow.
What kinds of things would you say that Obama could do