Thanks for more HERO!
Personally I see no issues with Hiro's characterization. Some years have passed (he was 20 during the East-West battle and should be around 32 here) and he has matured and improved a lot as a player. He was never particularly bad, a lot of his issues were caused by his lack of experience against skilled gamblers, which is why Harada destroyed him multiple times with his psychological tricks. Hiro also lacked the confidence to win, he used to see himself as a burden on Ten and Akagi. But Akagi's words inspired him to follow his dreams and that's why he was able to actually improve. At least that's how I've always seen it. After all, Hiro was already very good at noticing small details in Ten, it's just that his opponents would use this skill against him.