Professional wrestling legend and two times WWE Hall of Famer Booker T who is a former five times WCW World Heavyweight champion and a former WWE World Heavyweight Champion recently revealed that he advised Bobby Roode, AJ Styles and Samoa Joe that they were wasting their time on TNA Wrestling.
TNA Wrestling did not become very famous for creating new stars. However, they gave some legit competition to WWE which has always remained the biggest promotion in professional wrestling. But it never looks like a huge threat in front of WWE, one of the biggest reason behind it being not focusing on homegrown talents.

Booker T Says AJ Styles, Samoa Joe And Bobby Roode Wasted Their Time On TNA
All the mentioned three names were some of the rare examples of the stars that TNA Wrestling actually created. AJ styles had to be the biggest star that was created by TNA Wrestling. Samoa Joe and Bobby Roode were some huge stars created and developed by the promotion as well.
TNA mostly focused on the wrestlers they brought from outside of their promotion, like Kurt Angle and Christian Cage. But the mentioned three wrestlers here were quite talented and they are still capable of being face off any promotion. But did they really waste their time on TNA Wrestling?

TNA wrestling created these 3 wrestlers themselves. If the world is familiar with these three names that is because of TNA Wrestling. They might not have been the best promotion to lift new talents, but these three talents are solely created by them. So we cannot say they were being wasted in the promotion.
AJ Styles and Bobby Roode are currently working in WWE while Samoa Joe has recently been released from the promotion. AJ Styles had been a main event star for a couple of years whereas Samoa Joe had been an upper mid card. Bobby Roode has mostly been a jobber. We cannot say they would have been as successful as they are right now if they did not work in TNA wrestling.
Booker T who is a former five times WCW World Heavyweight champion and recently spoke on his Hall of Fame podcast where he revealed that he advised Bobby Roode, AJ Styles and Samoa Joe that they were wasting their time on TNA Wrestling. He said;

“When I first got to TNA, Roode, Joe, and AJ, they will tell you, I said, ‘Hey man, you guys need to get the hell out of here. Quick.’ I’m serious. I said, ‘You’re wasting your time,’ he shared.
“I told Roode, ‘Man, cut that damn mullet and get out of here as soon as your contract is up’. I’m serious. That’s what my advice to these guys was because I thought when I got there, I was gonna make a difference in the trajectory of these guys and because I wanted to make them stars. I wanted to do stuff with them to make them bigger.
“I really wasn’t worried about myself at all. But when that didn’t happen, I was like, man, you guys. I knew I was gonna be getting out as soon as my contract was up, so I was telling those guys, ‘Man you all need to think about your careers.’”
H/T to WrestlingNews.co for the transcription