Unfortunately, I have no idea what happened ten years ago, because I have only been active in the game and on the forum for a year, but I suppose that for such a long time everything has changed dramatically and you can see it at first glance. Recent updates have proved that nothing is impossible, but I realize that it is difficult to combine the fun of the game with its balance.
Daizo listed some very interesting and significant examples of genjutsu, and I just mentioned the so-called "Release technique" that would area-cancel all genjutsu effects, people with high intelligence stats may be completely immune to it, which will also significantly reduce genjutsu abuse, as not every opportunity will be suitable. Additionally, casting genjutsu may slow the user down temporarily, but this is an issue for debate.