Gusion revamp is honestly a buff that made him ban worthy.. a Gusion can literally kill a tank that has both Athena shield and radiant Armor with just one combo and no penetration item.
As Gusion player, It's not bad but I still prefer other item. Genius + calamity enough to melt heroes, doesn't need more magic penetration from glowing wand
I think gusion is better with items that have high magic power because his magic power scaling is high. One time I was using lolita against enemy gusion, I had radiant armor and he still bursted me easily(this is before glowing wand buff) Chang'e benefits the most from glowing wand, because of her skills low scaling and low damage but high volume. Harley too.