If you could change 4 Supreme Court cases what would you change

[politicallefty]

Korematsu was never overturned

That may be true, but it doesn't really apply today. (And I say that as someone who believes that Korematsu was the absolute worst decision ever handed down by the Supreme Court.)

As for my answers (in terms of cases that still apply):
-Buckley v. Valeo
-Kelo v. City of New London
-Santa Clara County v. Southern Pacific Railroad
-FCC v. Pacifica Foundation

[politicallefty]

Can someone explain to me the massive dislike of Kelo v New London? I get that if you have a massive distrust in corporate entities, it seems like a horrible path to go down. But wouldn't that distrust lead to opposing basically any private contracting from the federal government? Apologies for my ignorance on the case.

This has been argued here in the relatively recent past. Based on my views opposing the majority in Kelo, I would advise you to read Justice O'Connor's dissent (not surprisingly, Justice Thomas' lone dissent is too far out there for me). It's not often that I disagree with the entire liberal-leaning majority (+Kennedy), but I think their interpretation of the Fifth Amendment severely abridged the rights of the people that the Bill of Rights are there to protect.

[politicallefty]

PA Redistricting Case in 03 (can't remember name)

Vieth v. Jubelirer? I do agree with you, but I'm not sure what the proper constitutional remedy would be. There was no majority opinion in that case, just a plurality with a concurrence from Justice Kennedy. If Justice Kennedy could be convinced of a remedy, it could be possible to end partisan gerrymandering. It was his concurrence in that case that gave me the now-justified optimism in the case to uphold Arizona's redistricting commission.