What would Gore have done differently than Bush in regards to the economy, though? I don't see much that he would have done differently.
The lack of the 2001 and 2003 Bush tax cuts would have had a significant effect on the economy, both for good and for ill. Though there probably would have been a milder, more sustainable tax cut passed in 2001 without the sunset gimmick the Bush taxcuts used to avoid running afoul of the PAYGO provisions. (No cut in inheritance taxes, or those on capital gains and dividends, while cuts in the income tax rates would have been skewed more to the lower end of the income spectrum.
With no War in Iraq to pay for, the budget would have been in much better shape both in the short and long term, which would have been a significant benefit to the economy.
BTW, Truman only won in 1948 because Dewey ran a very poor campaign. I seriously doubt McCain (the most likely 2004 GOP nominee, in my opinion) would have repeated Dewey's mistakes.
Given McCain's performance in the 2008 campaign, I can't see him as running a good campaign if the primary issue in the minds of the voters is the economy.
Typically if the economy is in a recession (or just came out of one), the President would get blamed, rather than Congress.
Doubtful under any President that there would have been a recession in 2003-4. At worst for Gore, the recession of 2001 would have extended into 2002, impacting the off-year elections negatively for the Democrats.
Also, the Republicans are much better at smear tactics than the Democrats, and thus they would have probably attacked and smeared Gore very aggressively in regards to his poor economic record and low job creation numbers. Thus I think McCain would have defeated Gore in 2004. BTW, who do you think the GOP would have nominated against Gore in 2004?
McCain would have been a possibility, but not a lock. Without being able to position himself as the anti-Bush of the GOP, I can't see McCain as being more than one of several contenders. Giuliani would have better able to take advantage of 9/11 in 2004 than he did in 2008. Huckabee and Tommy Thompson would also likely have run. Probably some Republicans who declined to run in 2008 would have sought the Presidency in 2004, while neither Romney nor Fred Thompson would have run in 2004. It's even possible that Dubya would have tried to set up a rematch with Gore.