Originally Posted by
Digifiend
It's only the golden age names who got completely revamped, and that's honestly no different to DC (DC kept Superman, Batman, Robin, Aquaman and Wonder Woman the same, Marvel did the same thing with Captain America and Sub-Mariner) - both companies repurposed other names for new characters.
I think if Marvel had taken over DC - in any era - the big name characters would remain intact, though they would either be continuity rebooted due to not previously existing in the Marvel Universe, or an event done to merge DC's Prime Earth with Earth-616. The teams would probably be jumbled up. Imagine things like Doctor Strange or Wiccan working with Justice League Dark, a Green Lantern fighting with the Avengers in space, Speed (of the Young Avengers) and Kid Flash having a race...
The Squadron Supreme would disappear, as they're a Justice League expy and would be redundant. And Aquaman and Namor would probably both need to be changed, as they can't both be king of Atlantis. Their backstories would have to be altered to make them compatible.