Definitely one of the best TV series I've seen. I think script is actually brilliant, swearing included.
BTW- your link is broken by the brackets, try: https://en.wikipedia.org/wiki/Deadwood_(TV_series)
I agree that the swearing is brilliant but since I watched it when it was on at first, I swear less and I just notice it more. I often find in some American series that the swearing is like jumps in figure skating where you know it's about to happen because they keep turning their head trying to get ready for the swear word.
The scenes between Ian McShane as Swearengen and Keone Young as Wu are masterpieces of comedy. I am reminded of Who's on first, or rather Wu's on first with added cocksuckers