I'm still diligently ploughing my way through Breaking Bad, I'm up to the start of season 4. I like how US programs are particularly sensitive to audience reaction and will change tack if needs be. Equally, cast and crew learn on the job and become more slick/polished. As a result, characters change (and I don't just mean 'grow') and themes are tinkered with. Anyone that followed House will have seen that, and Breaking Bad is doing it too. I like it more now than I did in series 1.
The character of Saul is instrumental in the changes. I'd be interested to see what they do with him in his own series but he clearly has to be fleshed out, become less 2d, to do that. The beauty of the way American team writing goes, there probably was a good deal of back story already sketched out for him.