I agree. I do think that Lift and Lopen are bit to unserious, especially in comparison with some of the other characters in the Stormlight Archives, and I feel that they aren't necessary or needed as comic relief because we already get that from characters like Pattern and Wit, where it fits significantly better. To be fair though, I only realize this when I am looking back on the books and actually thinking about it. Lift and Lopen are still some of my favorite characters despite this, and I really enjoy reading about them.
Adolin annoys me. I don't really know why, but he does. Maybe it is a combination of him just seeming to be too perfect, and honestly more there to support Shallan then anything else. I just find Adolin really hard to relate to I guess.
I am not a fan of Mistborn Era 2 or Warbreaker overall, and those are easily my least favorite cosmere books. For MB Era 2 I think it might be more the setting that bothers me. Personally I dislike most industrial settings that don't have totally modern technology, not really sure why, just not my type of books. For Warbreaker, I think the reason why I didn't like it is because it was harder to get attached to the character, such as Lightsong. In Mistborn you had a full 3 books to get attached to Vin and Elend and Sazed and Spook, but in Warbreaker you only had 1, and I don't feel that it was enough to communicate who the characters were, and so it was difficulty to get attached. I do feel that characters such as Vivenna and Vasher's future in the cosmere could be much more interesting.
I am actually kinda happy that Brandon has not yet published Dragonsteel, because I feel that if he feels it isn't ready, then it probably isn't ready, and that it would be a lot worse to get a poorly written book with a poor plot to set off the beginning of the cosmere than to wait a while and get a really good one.