He would have been a lot of better in my opinion. This might seem strange, but do you want to know why????
Because Triple H's a very good wrestler. He has proven that time and time again. Look, how many classic matches he has had with other greats like The Undertaker, Mick Foley, The Rock, Stone Cold Steve Austin, and Shawn Michaels. He can even carry Batista and Randy Orton to a great match.
Triple H had a very successful career in WWE. He's a 13 time World Heavyweight Champion, multiple time Tag Team, and Intercontinental Champion, Royal Rumble 2002 Winner, second Grand Slam Champion, etc. He's The King Of Kings and has defeated his peer Legends such as The Undertaker, Mick Foley, The Rock, Stone Cold Steve Austin, and Shawn Michaels.
The only lowpoint of his career is his HATERS. Because of his marriage to Stephanie McMahon, his haters have the opportunity to look for excuses to tarnish his Legendary Status. His haters can just deny his greatness and say the reason he's so successful in his career is because of his marriage.
If Triple H didn't marry Stephanie, his HATERS would have never got that opportunity and still be as successful in his career. In fact, you can see before his marriage, he already became a Grand Slam Champion and five time World Heavyweight Champion. He really earned that, because he has worked hard to earn those. He worked from bottom when he was just a jobber and get suspended, and later changed his attitude, and eventually climbing to top of the mountain with his impressive wrestling skill and charisma. Remember, when Triple H was in DX stable, how charismatic he was. He did a lot of impressive things : impersonating Nation Of Domination, invading WCW, etc.
So, Triple H will be still be as successful in his career with as much accomplishments he had now and Fans won't be able to look for excuses to tarnish his greatness if he never married Stephanie McMahon.
@Only One Showstoppa : How in the blue hell you say after Triple H married Stephanie, he got lazier??? Triple H still worked as hard. When Stone Cold and The Rock left WWE in 2003 (after Triple H's marriage), Triple H single handedly carried Raw on his shoulder. The reason why he became the Face of Raw and hogged the spotlight at that time is because no one is credible enough to be Face of Raw. As you can see in 2005, when John Cena came to Raw, Triple H is no longer the Face Of Raw.
And during those times in 2003-2005, Triple H has also had a lot of great matches with Kane, Ric Flair, Batista, etc. After that, when he was no longer Face of WWE, he still put on great matches. He also put over John Cena at WM 22, Randy Orton at WM 24, and Sheamus at Extreme Rules 2010. He also had classic matches : DX vs McMahons & Big Show Hell In A Cell 2006, vs Randy Orton Last Man Standing No Mercy 2007, vs Jeff Hardy all the time in 2008, and of course vs The Undertaker at WM 27.