Fortunately, historians are not that shallow. They actually determine the causes of events, and not just the fact that they happened on someone's watch. The idea that Bush is responsible for the current financial crisis is half-baked at best. The Israel/Palestine criticism is shallow as well. Blaming Bush for 9/11 is also ridiculous.
1. Current Financial Crisis
Bush oversaw what is certainly one of the biggest spending administrations of all time. The national debt doubled on his watch and at least some of the current financial crisis is a result of the Bush administrations fiscal irresponsibility and its crony driven approach to governance.
The Democrats deserve blame for the Freddie Mac and Fannie Mae disasters at least partially, but the reason why the founders didn't put the congress in charge is because congress is almost always partisan, corrupt, fractured, and completely incapable of running the country. Bush was in charge. Bush said he tried to warn people. Who, if not Bush, was in a better position to do something about the mess. At the very least there was the bully pulpit which Bush chose not to use for this issue.
Bush managed to get the corrupt medicare drug plan through a Republican controlled congress. Why couldn't he have gotten some Freddie Mac/Fannie Mae reforms through the same congress?
2. Whatever your views Bush's attempts to do something about the Palestinian/Israeli conflict things have not made things better. I think he contributed to the problem because I think he did the wrong things. But whether you agree with me or not about that, the fact is that whether he did the right or wrong things nothing got better.
3. Whether 9/11 could have been prevented or not and by who is a reasonable question. The Bush administration clearly focused on the Star Wars defense ideas more than terrorism in their early days and it is not clear that Condoleeza Rice's inaction didn't contribute to the US vulnerability. *
* My personal view is that the FAA coupled with the airline industry was the entity most responsible for 9/11. There were at least two significant incidents in the world prior to 9/11 which suggested the possibility of suicide attacks similar to the 9/11 attacks. The industry coupled with support from the FAA chose not to take the most straightforward steps to do something about it. And that was to install secure flight deck doors.
Instead the US and the world have incurred costs in the hundreds of billions of dollars because the airlines chose to save a few bucks.
ETA: On the historians aren't that shallow.
On the polls of historians I've seen Bush is seen as being amongst the 10 worst by the vast majority of the polled historians. Usually Buchanan is brought up as some sort of bell weather for really crappy presidents and many do compare Bush favorably to him, but beyond Buchanan I don't recall any other president that was viewed so unfavorably as Bush by the historians. So at least a lot of the polled historians do seem pretty shallow by Sefarst's standards.