Why does Rebooted get such bad reviews?

I often see people say that Rebooted is a failure overall, with a good ending, but I don't quite understand. Of course, I think Seasons 1 and 2, as well as 4 and 5, of Rebooted are much better than Rebooted, but I don't think that's a reason to downgrade Rebooted. Ninjago was originally supposed to end in Season 2, and I think Rebooted brought Ninjago back to life quite naturally. They also made good use of elements from previous seasons, like the forgotten Golden Weapon and Serpentine. It...