I get your point, but what about the fact of the development that we've seen in Walt's mind? I mean, I think the writers are making it clear where it all comes from: he knows he's the best at what he does now, which is the exact counter-part of what he used to be (high-school teacher, not even college proffesor), and what he could have been had he not sold his share of the billion-worth project he mentioned the other day (and of season 1). Also, a lot of people has died, and he managed to kill Gus Fring himself, so he knows he can be the emperor.
I mean, I can see why some people might think the character is too over the top this season, but I believe the writers are making it clear where it all comes from and how it has developed.
Remember the half-measures full-measures talk that Mike gave Walt? It's curious to watch it again and to think of how Mike died. He was very, very cautious, but his half-measures might have costed him his life.