Jim Cornette was a figure present for some of the greatest non-WWE wrestling to happen in North America. As a figure who came up in the territory years (when there were dozens of smaller, regional promotions to employ wrestlers), he was educated the way most old school wrestlers: You keep things realistic and logical, and you don't insult the fan's intelligence or expose the industry, because then you damage not only the industry but everyone's bottom line.
That sort of philosophy stayed true for many all the way into the early nineties, despite the trend towards colorful characters and costumes from the WWF. While there were characters similar to say the Ultimate Warrior across the territories, the traditional presentation of a wrestler was more akin to a Ric Flair or a Ricky Steamboat or a Sting. You were a wrestler first and foremost, and your character developed from there. You were Ric Flair, a rich talented super-athelete who made love to beautiful women, enjoyed the finest drinks and hotels and flew in a private plane and was driven by a limo. You were Ricky Steamboat, a husband and a father who stood for a set of principles that others might call old-fashioned but you tried to uphold as a model for younger children. You were Sting, the high-energy face-painted warrior who was quick to trust and was always respectful of those who came before him.
All these "characters" and more made sense, because the wrestlers and promoters never forgot the framework the industry grew from. You generally had a personality, you had a set of skills that made you a threat in the ring, and you were fighting for your bottom line. Beyond that, you could have personality conflicts, you could make an enemy or make a friend, and that could lead you into tag team action or singles action. You could want to compete in tournaments, you might want to wrestle overseas.
You'd have all these little bits and pieces that when put together gave the image of a professional combat sport like say, boxing, but a "sport" that was very familiar and close because it was in every city in America (give or take). People came to the shows because they wanted to see the wrestlers be wrestlers and wrestle, and they wanted a reason to be invested in the show. A pretty boy to draw the young girls in, as they still do in Japan. A rough looking fellow for the beer-drinking blue collar guys to relate to. A cool looking guy to draw in the twenty somethings. An older wrestler, for the appreciation of the elderly fans who might remember seeing that wrestler while they were growing up. So on an so forth.
But you asked about Cornette, and not his views on wrestling. As I said before, he was someone that came up in the territory days, and was around for a lot of the great moments in history. From 1983 to 2013, he was around for the rise and fall of Jim Crockett Promotions, it's transition to World Championship Wrestling. He managed the Midnight Express against career rivals in the Rock N'Roll Express, worked incredible angles with the likes of the Four Horsemen, Dusty Rhodes and Big Bubba Rogers among others. He was a creative man during the early WCW years, ran his own promotion in Smokey Mountain Wrestling (best described as the last gasp of the territory days) and worked for years in the WWF as a manager, road agent and creative man.
One of his bigger contributions is the Hell in the Cell structure (IIRC), but he also provided a lot of talents for the WWF like Kane, Bob Holly, etc... who went on to be featured performers and would later run their developmental program in cooperation with Ohio Valley Wrestling, which he co-owned.
After that, he worked with TNA for several years before leaving for ROH, before largely leaving the wrestling industry for semi-retirement. With both he was an on-screen and backstage presence, and had significant influence (if not major in ROH) as related to booking and creative direction.