Had MM stuck to it's guns, they likely would eventually have wound up more or less where they are now but without the characters. The move to try to integrate an edgier "DC" presence into the park (unthemed but heavy thrill rides named after DC IP) would likely have still been a drive to push heavy thrill into the park... for instance, zForce at Great America Gurnee got moved around the country 'till it landed at MM as Flashback, same as several other MM coasters.
IF MM branded themselves as a character park, they'd likely have to put more work into them. As it is, the characters are at best a distraction and at most probably have resulted in some pretty crappy content being forced into the park.
I think perhaps a better way to view whether characters are important in a given spot/theme/park is to look at *why* they are there. KBF redesigned itself to incorporate the Schulz characters in a fairly expansive new area, and the area held it's own until the internal "revisions" started to fray the edges.
MM took the opposite route - they took existing or barely themed rides and slapped an IP on them without much consideration or work to make sure the park itself "fit" with the adds. Bugs Bunny World had no real reason to be where it was and it was/is difficult to determine exactly where the land starts and stops even using the rides as a guide. The DC area's spread beyond the initial scope while also watering itself down to mean it can be difficult figuring out if there's a unified DC presence in the park or if someone with a big superhero jones is naming the rides and calling it a day.