I actually quite liked 2049 and Dune. I say this as a fan of the original Blade Runner, Android Sheep, and the novel "Dune."
For 2049, maybe its just my own personal struggles with personal identity and losing people I love, but K's struggles resonated with me. Its a story that mostly says, at least the way I interpreted it, that who you are doesn't matter so much as the actions you perform in life. K, for most of the movie, is doing what other people tell him to do. In the end he takes action and makes choices that are meaningful to him. It results in his death, but it was a choice between either being a dead man walking with no meaning in his life, or finding meaning even if it means dying for it.
I can see why someone might not like it...its slow and it focuses more on the internal struggles of the main character than action on the screen. Still, when I ponder what happens in the movie, it resonates with me and lots of other people. Its pretty much a modern cult classic...did poorly at the box office, but certain types of people(including myself) are crazy about it.
For Dune, I agree it could be a bit dry. I love the book and I was a bit disappointed that the interactions were not as passionate, especially between Paul and his Mother. Still, the cinematography was amazing and they did the best they could IMO. Dune is a slow book that is hard to adapt to the screen so I am quick to forgive it.