The Stimulus was 100% Obama. Bush did not write, sign or implement that bill.
Romney was governor of a state and signed a bill for healthcare in that state. How is that hard to understand?
Unemployment and economic growth are affected by federal policy (taxes, regulation, etc.) Obama has an anti-business regulatory ideology and the economy reflects that
On banking regulation Senator Obama was against reviewing and revamping the sub-prime mortgages where GOVERNMENT mandates forced banks to make loans to people everyone knew could not pay them back.(This was of course prior to the 2008 crash) Yes, the feds would punish banks who did not make loans to people who they knew could never repay them on the basis of 'fairness'.
Breaking banks into two groups, investment & lenders would do what you ask in 'breaking up' banks. There is no such thing as 'too big to fail' only 'too corrupt to fail'.
I would consider anyone who has been successful as a citizen to be president. Obama was a bad student, professional protester, periodic lecturer and absent Senator. Romney is not savior, but 4 years of improved economics couldn't hurt in my opinion.