Well, Playboy was certainly an improvement over National Geographic.
Playboy made sex respectable, and it certainly linked sex to sophistication and as a natural part of one's lifestyle. It took the existing hypocritical puritanism, the wink, wink, nod, nod, say no more, and shook it by the throat. You not only had a gorgeous centerfold to drool over, you had a lot of great writing, and great cartoons, Jean Shepherd and Gahan Wilson come to mind.
It celebrated female beauty, and was relatively tame compared to Penthouse, much less Screw. Porn it was not.
Did it objectify women? Yes, but no more than fashion does. And it celebrated that women were smart and accomplished in ways that went counter to the thinking of many men. Playboy reinforced some stereotypes, but it also blew apart others.
It caused some harm, it certainly did some good. It probably caused more than a few Church Ladies to have heart attacks.
I'm grateful to Hefner for donating a very large sum of money to help save Mount Lee (site of the HOLLYWOOD sign) from being covered up by a pile of McMansions. Because of his generosity, more open space has been preserved for people to enjoy.