That's not Gaudreaus problem at all. He's never had an issue with people trying to hit him or even taking a hit. Show me one hit where Gaudreau actually gets injured. It hasn't happened. His problem in the playoffs is his linemates, Monahan, who is 6'3 205 lbs, and Lindholm, 6'1 195 lbs, play like soft players too.
A player like Gaudreau can be successful in the playoffs when he has linemates willing to set up shop in the dirty areas or fight for pucks in the corners because a small guy like him will always struggle in those spots. What Gaudreau can't do by himself in the playoffs when the whistle is put away is be a one man show (although he has done it in the playoffs before, even game 5 he just couldn't finish) because everyone just converges on him. During the regular season, they try to converge on him and shut him down by hacking and slashing him and take a penalty, in the NHL, for some reason we have two different sets of rules and those same slashes aren't called in the playoffs.
MSL had Richards and Lecavalier. If those two played like Monahan does, shying away from hits and the corners, than MSL never wins a cup or a hart.