Related: 'George W. Bush is smarter than you'. Elite leaders often make themselves look dumber than they really are. https://keithhennessey.com/2013/04/24/smarter/
The Iraq war was architected by Cheney / Rumsfeld, Bush playing an incidental part at best. The invasion of Afghanistan demonstrated a studied lack of historical knowledge and the failure points of previous attempted invasions. Charitably, he does get credit for kickstarting the drone program which gave the US a credible (if ethically suspect) deterrent to terrorist organizations. However BO gets deserves more credit for deploying both the physical and legal apparatus to make routine drone strikes, particularly in places like Pakistan, a reality.
As for the economy, the tax cuts were a core Republican party agenda item since Reagan. Bush did not drive that, Congress did. Privatization of Social Security? Failed. Immigration? Same. Foreign policy? Besides alienating allies via needless wars, nothing noteworthy.
That leaves two things, foreign aid and No Child Left Behind. The former was a legitimate accomplishment and for that GWB should get credit. The latter had mixed results.
Then again an above average presidency does not a supposedly smart President make.