No offense, but a lot of what you spew out on here is very "close minded" as you often only refer to fangraphs for your info when judging players. Its not that I disagree with your assessment of Miller, I actually think he is over-rated, but that article he listed does bring up some interesting points. The fact that he added 2 new pitches, and one of them (cutter) becoming top 3 among SP, can't be analyzed with a simple glance at his ERA/DIPS differential. NJH, he actually did improve, at least anyone who ever played baseball would agree is considered improvement. While the comparison to Arreita is a huge over-reach, at least the author has some tangible evidence as to why he came to that conclusion.
To write off Miller using metrics from years prior when he was a 2 pitch pitcher, is like referencing Dickey's stats before he threw the knuckleball. That's pretty close minded IMO