The Sequels' shiny veneer covers up movies with no substance. The first movie was an uninspired re-skin of A New Hope. The second was a boring movie that ruined its characters, including Luke Skywalker himself. And the third was a pandering mess that tried to cover failure with spectacle.
Plenty of blockbuster films look good. There are plenty of special effects and even top-of-the-line actors to go around, like in the Disney live-action remakes. That doesn't make them good movies. The same goes for the Sequels; just because they look nice on the surface, it doesn't mean they're free from criticism.