RotR and Web Slingers are terrible comparisons for each other.
Now of course, by the time the Multiverse E-ticket actually opens for AC, it would be a great time to do something to fix the storyline for WEB Slingers. I do enjoy Web Slingers, but I realize it could be better. I just don't see what really can be done though. I guess the story could be changed around to add actual villains, but I don't have much hope for something like that happening.
The RotR for Avengers Campus has yet to be built (the Avengers E-Ticket needs to be on the level of Rise or around there). Web Slingers is best compared to Smugglers Run, which hasn't necessarily held up great itself in terms of wait times out there. I was out at DLR two weeks ago now for Labor Day weekend and the wait for SR hovered around 30-50, which was about the same as Web Slingers held to my whole trip. I actually have a picture with absolutely no one standing in front of the Falcon on a Saturday afternoon. The rest of the park was packed.