I personally rarely ever use a high-draft pick on a d-man. My typical draft strategy is to lock in an elite goalie in rounds 1-2, and lock in a second #1 goalie in rounds 3-4. I make sure I lock up an elite forward within the first 2 rounds (usually first round). I don't usually draft my first defenseman until round 4 at the earliest, but usually round 5-6.
I think it's too risky to use a high pick on D. If you look at the last 10 years, the d-men point leaders are all over the place - there is no consistent 70+ point threat. There's usually 1-2 guys in the 65-80 point range, and the rest fall into the 55-65 point range... it's too much of a crapshoot to predict who the 65-80 point scorers will be.
Forwards on the other hand are much more reliable and you know with reasonably accuracy who the top 1-10 scorers will be.
Another reason to draft d-men later on, is because while there are only a very small handful of 65-80 point guys each year, there's a huge glut of 45-55 point guys, and you can easily pick these guys up in the mid-late rounds.
To answer your question, I'm also starting to come around to your view that Doughty is overrated. I don't know if it was the concussion or if he was just a one-year wonder like Keith, but he doesn't look the same as he did 2 years ago.