Ray Bourque wasn't an overly physical defenceman, either. Coffey had some seasons with big PIM totals, but nobody ever confused him with Scott Stevens.
Coffey's playoff record isn't as spectacular as some might think. Yes, he won four Cups. Can't take that away from him. And he had a couple big playoffs. But in 1987, he was injured for a good chunk of the year, and part of the playoffs. When Coffey has 11 points in 17 games, he's probably not going to be on Conn Smythe ballots. In 1991 with Pittsburgh, he suffered a serious eye injury at the hands of Fetisov and missed almost half of the Pens games. (I could go into the argument that the Oilers, Pens and Wings all won the Cup in the year they traded Coffey, but I think that has more to do with the return package).
I've always said "tell me how the player played the game. Don't talk to me about stats and awards." This is especially true with defencemen. Lidstrom might have a slight edge on Chelios and Fetisov for offensive ability, but both are Lidstrom's equal defensively, and both were much more physical. I'll argue that Chelios was a better leader, too. A 40-year-old Chelios nearly beat a 32-year-old Lidstrom for the Norris in 2002.
Lidstrom won three Norris Trophies, and you can't take those away from him. But in those three Norris seasons, he beat guys who were roughly 40 years old. As John Flyer Fan astutely pointed out in the last poll, the number of great defencemen to be drafted after Stevens in 1982 has been severely lacking. (Lidstrom and Leetch are the only two blue-liners picked since then who are locks for the HHOF, although Niedermayer and Pronger are inching closer). None of Lidstrom's Norris seasons are as good as Bourque, Chelios or Coffey's.