You know, there is one thing about Bush that no one ever talks about, and it surprises me.
When Bush became president, gas prices were about 1.65/gallon. During his time as president, gas prices shot up to over $4 a gallon, and oil companies made record profits. Bush left office, and gas prices settled, and while you can debate whether they are sustainable at their current levels (they probably aren't, and will climb again), we are still a long way off from a $4/gal becoming something standard. More in the mid-$2s, probably, which would be maybe at the high end of historic price levels, with inflation, but nothing extreme.
It always surprises me that Bush doesn't get more scrutiny for the massive profits by his oil business buddies while he was president.
it's not so much foreign policy legacy, more of a domestic legacy, but I will always remember Bush as the president who first saw gas prices shoot over $4/gallon in the US, and oversaw record profits for the oil companies. And given his background, I don't think that is good association to have.