I don't know about the wing loading and I doubt that it was high on the F-20. The thing weighs just over 5,000kg, quite lighter than a J-7E at 5,300kg. With that less weight, the F-20 screams with a TWR over 1.10, better even that of the F-16A/B.
The plane is a bit of a hotrod, but it was also plagued with sheer bad luck. The Reagan administration seems to have something against it at the get go, when they refused Northrop from selling the plane to the Taiwanese as the Reagan Administration courted Beijing. To add insult to injury, they called General Dynamics to secretly assist the Taiwanese in developing a new indigenous fighter, one that had Northrop like features such as
---twin Garret bix engines, ironically originally proposed for an engine upgrade of the F-5 (F-5X)
---uses the same APG-67 for the Tigershark
---uses LERX to divert airflow into the intake at high AoA, something Northrop designed first for the F-5, then the F-5E, the F-20, the YF-17 and the F-18 series.
