I rewatched the show last month. When I first watched it back then I felt the same as you. When rewatching it now, it made more sense the way things evolved even though some parts seemed rushed. It’s a nice show and well tailored 
. Indeed it’s more entertaining in the beginning because of the plot, boldness of Walter and the “transition to bad” part, but the story is well made and it gets more mature as we see how the characters evolve and what are the consequences of the imoral actions, and the unstoppable wave of events they create, that cause dramatic events and suffering for all involved.