It was based before Hogan and Bischoff but they admitted they didn't get the concept and tried to force gimmicks on top of gimmicks to it - including a weight limit
Then wwe started pandering to smarks with NXT and too many boring cruiserweights entered the business
The X Division was based during the Jarrett era of TNA because it was genuinely different. WWE wasn't doing flippy shit (even with a cruiserweight division). And TNA's main event and tag scenes were a mash of wwf/wcw stars playing their hits and schmozzy bloody walk and brawls
Jarrett and Borash came up w the x division to be the "x games of wrestling" and it stood out because it was genuinely different and they still tried to give characters to the wrestlers: low Ki, Jerry Lynn as the vet, shark boy and curry man, macho man jay lethal, Sonjay duty, PCO in a mask, flying elvises, suicide, AJ Styles as the ace, motor city machine guns, same Joe as the heavy, team canada, random crossovers from NJPW and Dragon Gate and CMLL and AAA.
Ultimate X was the last great gimmick match
And TNA found a good formula of: stars in the main event, solid tag team division with good feuds, knockouts division with Kong, Gail and beautiful people and the X Division