Actually, Selke voting didn't really change much....maybe a bit. It was the players that changed, that was the biggest factor. Through the 2nd half of the '80s and 1st half of the '90s, the biggest change in the NHL was coaches coaching defensive hockey, and this was most manifested in the forwards. So, the pool of good (and great) defensive forwards increased substantially, and that's why offensive stars started to get more Selke votes....i.e. they WERE actually better defensively.
A recent guy like Bergeron, for example, was a LOT better defensively than guys like Clarke, Trottier, Messier.
The defensively-deficient hockey of the '70s and '80s was such that you could very easily spot the good defensive players, like Gainey and Carbonneau, who was probably the smartest forward positionally in NHL history up to the that point. But he has company now.
Same with defenseman....guys like Savard, Langway, Lowe, Ramsey, etc. stood out like a sore thumb.
But the pool of good defensive forwards is a lot bigger now.
