As I have only been on coasters in the South, my input is limited, but the most overrated coaster for me was Incredible Hulk. Sure, the launch/zero g roll is fun, but everything after the first corkscrew is pretty boring. It's still an 8/10 for me because of the forceful cobra and giant loop, but it shouldn't deserve all the fame it gets. Dragon Challenge is amazing though, don't get how anyone thinks that's overrated.
First runner-up is Rock N' Roller Coaster at MGM. The Launch, like Hulk, is fun, and so is the sea serpent roll at the beginning, but then there's like 5 bunny hops in a row, MCBR, bunny hop, corkscrew, another 3 bunny hops and then the station. Sure it might be cool for someone who has only been to Disney World, but it shouldn't be considered Disney's "extreme ride", I found Space Mountain much more fun, and maybe even more intense because of the intense lateral g's.
However, SheiKra is in no way overrated for me. Yes, it's short, but the vertical drop and immelman are both epic, and even that second almost vertical is still really fun. Maybe I'm spoiled because my wait was only about 45 min.