One of the best features of DS2 is it really improves the deeper you get, whereas DS1 kind of plateaus around Sen's Fortress/Anor Londo. Particularly in terms of level design, I think you'll find a lot to enjoy in the DLC areas, so your opinion may improve.
As I wrote earlier, I found DS2 the most difficult game in the series to start with because a lot of the techniques I felt I mastered in Demons' and DS1 really didn't serve too well. However after adapting my approach and playing through enough cycles to platinum the game all that had changed and I was really having a great time.
The game definetly gets better the more used to it you get. And although I myself did a thread saying how much I disliked DS2 compared to DS1, I never thought it was a *bad game*.
The DLC areas that you mentioned are a proof to how good it can be sometimes. The dragon boss fight in the sunken king is probably my favorite boss fight of the entire series (haven't played BB, tho).