Haven't watched it but I know it probably sucks
From what I heard it's cause of the Bad Meta Comedy
Giving Velma a holy-er than thou personality
Making fred a stereotypical spoiled white rich kid
Not including Scooby
The love triangle of Velma, Fred and Daphne with "Shaggy" just being left out even when he declared his love to Velma and she brushed it off as a joke
And etc etc