Firstly massive increase in government regulations would have shut down the American economy long before the crash and Great Recession. As would the lack of Bush tax cuts.
Secondly, Bush got to appoint two Supreme Court justices: Alito and Roberts. While neither have been as stalwart Originalist as many Conservatives wanted, Kerry likely would have appointed radical leftists to the Court (as Dems ALWAYS do)... and with the death of Chief Justice Rehnquist in 2005 you'd likely have seen Kerry appoint Ginsburg as Chief Justice.
So basically, you know how the court is presently 6-3 Conservative leaning? Yeah, it would be 5-4 Liberal Leaning with a Liberal Chief Justice. This means the following critical cases likely would have been decided differently, trying to stick to the 2006 - 2012 timeframe as going beyond that becomes harder to say that these cases even would have come up:
Shelby vs Holder - Which struck down preclearance of many State's electoral maps that had artificially been boosting Democrat numbers in the House due to requiring majority-minority districts etc.
Gonzales vs Carhart - Upheld a ban on Partial Birth Abortion at the Federal level.
Burwell vs Hobby Lobby - Enforcing the Free Exercise clause and allowing closely held corporations (that is corporations held by a single owner) to make policy based on the owner's religious beliefs.
Dobbs vs Woman's Health Organization - Yeah, this is obvious, but you'd never have seen this one come up, the court would have been to closely tied for it even if Ginsburg had been replaced by a Republican.
Janus vs AFSCME - This overturned mandatory union fee payment by non-members.
Town of Greece vs Galloway - This allowed non-sectarian voluntary prayer at the opening of town council meetings.
DC vs Heller - Made explicit that the 2nd Amendment applies to an individual's rights and basically shifted the entire gun control debate onto ground favorable to gun rights advocates and against gun control.
McDonald vs Chicago - Companion case to DC vs Heller in the shift on Gun Control. Held that the 2nd Amendment applied to the States via incorporation via the 14th amendment.
Medellin vs Texas - Held that International treaties are not binding domestic law unless Congress enacts statutes implementing them or unless the treaties are self-executing. Also, decisions of the International Court of Justice are not binding domestic law, and without authority from Congress or the Constitution, the President lacks the power to enforce international treaties or decisions of the International Court of Justice.
Basically the Religious rights would be weaker, gun rights would be weaker, unions more powerful (and thus MORE power to the Dems than they already have), Abortion would be massively expanded, and pretty much the entire situation in the Supreme Court would be so utterly different that it could potentially change EVERYTHING.
So yeah, want to know how much worse it could be: without W. Bush there would be no conservative majority on the Court and we would have had a liberal dominated court for about a decade, which means there would have been no real checks on the Dems push for socialism.