Originally Posted by
Tizzy_Tormentor
They've never stated Zidane as an inspiration, they added a double sword job because that's the most requested weapon they've been asked for, they even name dropped Sword Art Online as the inspiration for most of the abilities/moves, which checks out, Viper is basically the anime swordsman class.
This is in contrast with Gunbreaker, which was very clearly based on Squall, borrowing the moves and stances from both his original and Dissidia appearances (and borrowing a little from Seifer) whereas Viper has no such thing from Zidane, with no moves or similar stances being borrowed. The only thing that suggests inspiration from Zidane is the Twinblade.