>>90023800I want to say Marvel, but the truth is that it hasn't been Marvel in a long, long time. They had some great interconnected world-building like
>>90024211 points out at one point and, unlike DC, the universe was designed to be interconnected rather than a bunch of unrelated characters gradually getting thrown to like in DC. When the editorial was tighter (I want to say the '80s at the latest, but some '90s stuff wasn't so bad in this respect) and they actively avoided continuity errors, it was pretty damn good.
The problem is that they've fallen from grace and Marvel is currently a clusterfuck. Continuity may as well have not existed for the past five years, and arguably for at least the past decade, which is a blow to the world-building among other things. I know that continuity and world-building aren't the exact same things, but it's continuity that allowed Marvel's style of world-building in the first place, with every writer basically adding more bricks to a foundation and on top of bricks already in place.
DC has always had a looser continuity, but tying it together with meta lore over the years has made it a lot more appealing in its own right and I feel like their world-building got better as a result, but Marvel was better at one point.