Remember that he inherited the mess of the Iraq War AND the greatest recession since the 1930s.

Russia - I think the US response to Russian adventurism has been very well calibrated and he has brought along Europe to enforce some pretty strong sanctions on Ukraine. When your coalition hangs together, you are doing a pretty good job.
Syria - Here I think the US messed up by overcommitting. As soon as Russia started flying air missions the US had to lower expectations for its range of action dramatically downward. They put their chips in and we were not gonna match them. On the good side, he did not commit ground forces or put us in a position where US/Russian forces might have an incident. So it was a limited mistake (talking big about a red line).
Libya - Again we overcommitted but at least we did not double down. Ultimately I think the outcomes in most ME countries are just choosing which bad you want.
Iraq - He had to get out with no status of forces agreement. And did so.
Afghanistan - He has not abandoned them, and we and the locals seem to be in agreement about the right level of troops and their scope of action. He focused on continuity here and a very slow drawdown.
ISIS - We were asleep at the switch when they invaded Iraq. But we did not have any forces in place to prevent it and Syria is outside our zone of influence. Without a commitment of US ground forces it was always going to be getting the Kurds/Turks/Iraqis to fight. Our credibility is still good with all of them even though they all hate each other.
Latin America - Obama has set the right tone with Mexico, Colombia, Brazil, etc. The far left countries were consolidating into an anti-American bloc and we probably got bailed out there by the big drop in oil prices.
Africa - We have been too overcommitted in the ME to devote proper attention to sub-sahara issues, many of which spiraled badly with little Western attention. Few good marks to hand out here.
China - Despite all the attention Obama has put into cultivating SE Asian countries, he has not gotten much payback for it. I think they would almost all sell us out in a heartbeat for a cushy trade deal with China.
Iran - the nuclear deal was a pretty significant win in that all the other options were far worse, and again he kept our coalition together.
Israel - I am done judging the US on how it handles the Israeli-Palestine conflict unless we get directly involved. We ain't fixing this one, and definitely not as long as Likud is in power.

Middle East generally - the focus on human rights, including women's rights and democracy has hurt US standing in Islamic countries significantly during Obama's term, as well as our continuing CT efforts (drone strikes). But I cannot say what Obama should have done differently - the cuddle with the sheiks approach of the Bush years just put under the surface a lot of the street anger we are dealing with today.

As a world leader, Obama has been a great representative of our nation and has rarely stepped outside the comfort zone of our allies (with the exception of in the Islamic world). Given the challenges he faced and the standard set by his predecessors, I am very satisfied. He made few situations demonstrably worse and those that he did he was able to change course and limit the damage rather than doubling down on stupid.

We are not fighting with or losing our allies, and I can point to few mistakes in the level of military engagement. The worst he can be accused of is that it took him most of his entire first term to become a realist, but he avoided major blunders in the meantime.