What made the Hall of Fame Equipment Set strong was not only due to its superior stat values, but it was also due to the three hidden attributes.
The first hidden attribute was the Pseudo Authority, Strip.
Authorities were a form of power that trumped even Territories. Coincidentally, it was also the highly-sought-after target of multiple experts in Li Yi's past life. Alas, the power could only be wielded by gods, and back then, there was only one player who had managed to ascend to godhood.
Since becoming a god was a pipe dream for many, most players had pinned their hopes on equipment instead. Many rare equipment pieces came with the precious Pseudo Authorities in King of Pantheon, and though their effects were not as potent as actual Authorities, they were enough to deal with the Territories.
Li Yi's Pseudo Authority was called Strip, and its effect was to Strip its target from using a particular ability.