The ROH Title by a long way. Because when you have the ROH Belt, you're the main guy. But with TNA, you can be overshadowed by someone else's feud, or it could just be put away for another feud, like the Main Event Mafia. ROH's belt has had more defenses in the last 2 years, and every champion that wins the belt deserves it.
so let me break the ROH title reigns down year by year, and you tell me which is more important.
2002 - Low Ki wins the title in a brutal one hour Iron Man Match. Every time he had a match, it was a MOTY Candidate, whether Champion or not. Ki was hands down the best indy worker that year, having great matches with Danielson, Styles, and Joe.
2002-2003 - Xavier wins the belt. He's ridiculously underrated as a champion. How he won was a huge shock at Unscripted, and he was probably the only true heel to ever hold the ROH belt.
2003-2004 - Samoa Joe. He set the standard for the ROH Belt. It showed that you didn't need some generic muscular guy as a champ. He didn't just defend the belt against the main guys, he wrestled everyone, in every style. A brutal match with a Briscoe, or the Trilogy with CM Punk is what this belt's known for. He was an absolute beast. He also made the Belt a World Title.
2005 - Austin Aries. He might have had a shorter run than Joe, but him winning the belt was one of the most exciting things in ROH History. He defended the belt everywhere, in Canada and Mexico. It set him up to be ROH's main players for the next 3 years.
2005 - CM Punk. He shocked everyone when he turned heel during his reign, starting his storyline with the WWE Contract. His reign was wild, and having him sign the WWE Contract on the ROH Belt was pretty amazing. He played the heel well, barely winning his matches when he would defend the belt.
2005 - James Gibson. He might have been a transitional champion, but he was a good wrestler. He showed that he wasn't some WWE wrestler, but he could go.
2005-2006 - Bryan Danielson. Probably the second best reign to Joe. He defended it against everyone too, and had a huge number of defenses. He defended the belt during the CZW War. Danielson was awesome as a tweener, even though he looks like Bob Backlund.
2007 - Homicide. Very big deal heading into him winning the belt, all the fans were behind him to beat Danielson. Winning the belt was a big, dramatic match. Though the reign itself wasn't great, just having the emotion of Cide as champion made it exciting.
2007 - Morishima. He was just a monster. He demolished everyone while still putting on great matches. His series with Danielson was pretty brutal, and it showed that he could kill some guy. He was the first foreign ROH Champion.
2007-Present - Nigel McGuinness. He transitioned from face to heel as his reign is going on. He's been pretty entertaining as a Champion, although now he's getting a little stale. He draws real heat by just using the style he wrestles, lariats and arm submissions.
TNA World Title for a simple reason:
ROH = no TV
TNA = weekly TV show.
Not to mention, the TNA World Title has been held by guys like Samoa Joe, Sting, and Kurt Angle. That alone makes it more important
OK, so by your logic, you're basically saying that the Intercontinental, US, or Hardcore Championships are more important because they're on TV, and they were held by famous people. Face it, ROH's Title means more, no matter how blind you can be.