Pretty sure near the end of his reign Hatton dropped most of his other belts and jus carried the ring and IBO belts
IBO is the one every fan should like. If more got behind them rather than just slag it as fake then it would help clean the sport. Slagging the IBO is usually a sign of simply not understanding. The real truths are the IBO's policies are better than the other 4, until it can enforce mandatories then it can't carry prestige like the other 4. The reason why a number of high profile boxers carry the title is they respect those policies, their $50,000 sanction fees per fight help keep it running.