Difficulty is a balance that is never going to be right for everyone. GT is explicitly not a visual novel: it does expect a little effort from the player to progress. But as RPGs go, this isn't a particularly hard one for the average player. I hate to be difficult, but for most people that are having issues, it's not even a problem of RNG, they just aren't playing smartly. If you don't manage your items properly, you're going to have a bad time. If you go into fights, especially big ones, without being topped off in health and energy, you're going to have a bad time. If you don't time your special attack, regular attack, and full heal actions appropriately to maximize what they can do, you're going to have a bad time.
Keep in mind that one of my main metrics for all of this is myself: I am NOT a skilled RPG player, by any stretch of the imagination. As soon as the mechanics of a game start to resemble tax preparation my eyes glaze over. If I can manage to play through GT, you should be able to as well.
But with all that said, eventually there will be an alternate route through the Host Club, specifically for those who would rather not take on the final gauntlet.