It's pretty simple: none of those tracks were created by PD. That's the problem!
Of course, people are entitled to their opinions. If folks genuinely think Tokyo is a great track, I'm having a hard time thinking of a fantasy track that would qualify as "bad" though. As others have said, it's a corridor procession. There are two spots you can conceivably overtake cleanly, and that's provided the person in front of you makes a mistake, or you take a lunge. There are no alternate lines: you can't cut back on someone via late apex, because the track is so narrow they'll be in your way.
There's also no real variety: the slowest corner in a Gr.3 is a 90 mph right-hander. The fastest? A 135 mph right-hander. The other turns that require braking? A 120 mph right-hander, a 125 mph right-hander, a 110 mph right-hander, and... whoa! A 105 mph left-hander.
There are other fantasy tracks, in GT and other games, that I don't find particularly interesting. But at least they offer options in terms of driving lines (and almost uniformly more interesting visuals). Citta di Aria and Amalfi were narrow with very little room for overtaking, but those were circuits designed to feel like roads, for dueling against a single other car. Not an 18-car field.
With such a small track count in GT Sport, Tokyo will be hard to avoid.