Have you spent much time playing other characters? Taking the time to learn Tianhuo herself may help you get a firmer grasp on both her strengths and weaknesses. Even if you choose to focus on one character, it is important to know how a character plays the game from their perspective. If you play Tianhuo for a while and just spend every day all day stomping on Arizonas then there very well might be a problem! I think that might be a better self-assessment tool than polling other people for their match-up ratios. If you become comfortable with Tianhuo and don't completely body Arizonas on the regular, perhaps that may also help to identify a strategy that they are using that you have overlooked?
My biggest issue with Tianhuo has been that, prior to the patch, she was able to simply ignore much of the neutral game by flying over it. Her flight speeds have been altered with the most recent patch (slower while rising, faster while falling), and that seems to have made a difference. I've not had as much opportunity to play as I would like since the patch dropped though, so I can't offer much in the way of concrete thoughts about her in particular. In any case, given the significance of the patch it seems sensible for the developers to watch and let things settle for a while before any further changes are made. Keep sharing your observations, and keep trying new things, but patience is likely the order of the day here.
Addressing the larger issue of fun: there are a lot of things about 2D fighting games that, well, simply aren't fun. Or rather, much of the time the fun comes from a particular kind of studious engagement, like learning to play competitive chess or go. These games are difficult to learn to play well, and the process of learning can feel like bashing yourself against a brick wall as you work through loss after loss. The composition of the scene itself makes this particularly difficult for newcomers because (like grandma's bridge club) the community appears to be populated almost entirely by terrifyingly skilled people who seem to have been playing these games forever. The learning curve to reach a level of competency for an even match with the average fighting game player is frustratingly steep. Even worse, unlike chess or go or bridge, when you are losing you don't even get a turn. If I'm getting destroyed by some 9 kyu in go, I'm on the defensive the entire time, and I know I'm losing, but at least I get to make decisions. Losing in a fighting game means not actually getting to play the game, as you sit through a combo that feels like an eternity, and this is a structural element of most fighting games that genuinely sucks. These are all legitimate obstacles to enjoying fighting games as a newcomer (even a relative one - and yes, even with 400 hours logged you're still a relative newcomer).
So I can understand your frustration. I hope that everyone else can take a step back for a quick second to recognize that even if they disagree with Koren's assessment of the match-ups, there is something intrinsic to the genre that makes playing on even a slightly uneven playing field (be it skill or match-up) kind of difficult to bear unless you're approaching it from a very particular mindset. The frustration is real. And not everybody is a monk.
That said, this is precisely one of the reasons why the stagger reset change is so beneficial to this game. Neutral is the one part of a fighting game that both players "play" equally. The stagger reset change means that it limits the length of combos and the strength of set play, and allows defending players the opportunity to reset back to neutral. Balancing individual characters is a matter of fine tuning. This kind of systemic change is a bold statement about what the developers believe the game should play like at its core. Everyone gets to play more of the game, not just the person with the longest combo. To me this decision demonstrates a commitment to the idea of neutral on the part of the developers that gives me tremendous faith in the game.
