Similar to Breaking Bad, Deadwood is also a western by genre. Of course, that is where the similarities begin, but they then diverge when you consider that Deadwood takes place a hundred or so years ago, and Breaking Bad happened yesterday.
Points of correspondence include antiheroes as lead characters, especially with Al Swearengen. C'mon folks. If you appreciate naughty language wielded with the deft touch of a sledge hammer, Deadwood triumphs over everything. HBO has a leg up on AMC, as HBO can pretty much show you every single inch of someone's body, whereas Breaking Bad only lets you see the goop that remains thanks to certain chemicals.
On a slightly more serious note, Breaking Bad's characters are driven to make choices, most of them out of their control. Of course, I'm only four seasons through BB, so bear with me on this. Deadwood
With antiheroes comes moral ambiguity. White and Pinkman are no strangers to the necessary and oft unnecessary aspects of their line of work, although both White and Pinkman live in a universe that could afford them differing professions. Swearengen and Bullock are two sides of the same ambiguous coin: criminal and sheriff. They are born in a time period where chance has placed them a foot from good and six steps from evil. In Deadwood, there is little room for stepping over a line most people think doesn't exist.
Inside the realm of ambiguity comes economics and policy. While Breaking Bad has elements of this, Deadwood showcases events on a larger scale: money runs this town and if this town loses money (or if the wrong people get more money) then the town burns to the ground. Thus the corporate aspect is more alive and colorful.
This next point will assist Breaking Bad fans. The pacing is similar. Both shows takes their sweet damn time in getting anywhere interesting, but when they do, hold onto your nickers.
In terms of sin, Deadwood and Breaking Bad are spooning bedfellows. Neither of them are interested in pulling punches in the name of your sanity and sensitive stomach. Both treat the human body in the same manner; a collection of flesh and blood that bleeds and breaks. Both show the mistreatment and subordination of women as a means to satisfy men, though Deadwood has a more physical aspect to the abuse. To both shows, sin is treated as an unstoppable infection that rots away everything until it can no longer use you to sustain itself.
Then it turns on itself, and subsequently, to you.
Among other reasons, that is why Breaking Bad fans should watch Deadwood. The points of correspondence are highly similar, but the thematic out-workings of each show are unique and powerful. Hints of spirituality and redemption peak through the grime, but only enough to showcase the oft futility of a life of rebellion and sadness and death.
Happy New Year.