Im not sure. To be honest, I dont find it's style to be particularly bad. Actually, I like that it resembles the original book's style more, and it's natural that the technology and style is bound to be better now than it was back then.
I feel like the issue people have with the style of THIS film is that it resembles the wacky fluidity of animated films nowadays, the kind of mario movie/illumination movie sort of bounciness to it that usually gets associated with wacky hijinks and the like. Because of that association, it feels weird to some I bet, to see it with Shrek. From the get-go, especially in 1 and 2, it's basically one big silly parody of typical disney-fairy tale shtick and its why the movies are so memorable, because they're riffing on what disney's done so much while also genuinely conveying a fun or meaningful story. Even in shrek 4/forever after, there's a genuinely nice meaning to valuing what you have and not taking it for granted in spite of the issues that exist in one's life, alongside accepting that the past is the past and doesnt need to be relieved. Cant say much about shrek 3, though I remember heavily disliking it.
I dont care about the design change so long as there's a genuinely meaningful story to be told, and that it isnt just gonna be silly-wacky hijinks - shrek is about parodying disney shit, and also conveying something with well intent. I HOPE that this movie keeps that up.