Can’t be overrated if most people consider this series bad/mediocre/average.

I don't know about overrated, considering some people call it bad or mediocre. In fact, I think it's slightly underrated, but I'll go with neutral.

I saw people say it's great and amazing

Almost everyone on this wiki despises the series. You can go back and see how the videos were recieved. A longtime member even quit SML using this series as one of the reasons.

Its overhated if anything

Perfectly balanced...