No one is trying to argue that Power is an eventual HOFer. That's never even come up in discussion. Lidstrom was brought up because he was a good defenseman (ok, far better than good) without being overly physical.
Ekblad is a good example of a fine defenseman who isn't overly physical that was taken 1st overall.
I still say Power's comp is an offensively hyper-charged Jay Bouwmeester. J-Bouw was never all that physical, but was positionally sound, could devour minutes and knew how to use his body even if he didn't punish others per se. Power is now showing real signs that he's learning how to use his body.