New Divine Fighting Technique: Vadar's Destroying Shield

In my homebrew campaign, Vadar is the Fire God of elves, patron of new beginnings and destroyer of all evil. The shield is his favored weapon, and as a warpriest devoted to him, Fiona Wylde uses his divine fighting technique in place of one of her blessings.
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Vadar’s Destroying Shield
The Destroyer transforms instruments of defense into powerful weapons of offense.
Optional Replacement: A chaotic good fighter or barbarian who worships Vadar can replace a bonus feat or rage power with the following initial benefit.
Initial Benefit: When wielding a longsword and a shield, your shield’s threat range with shield bashes doubles.
Advanced Prerequisites: Bashing Finish, Fortified Armor Training, Greater Shield Specialization, Power Attack, base attack bonus +10.
Optional Replacement: A chaotic good fighter or barbarian who worships Vadar can replace a bonus feat or rage power with the following advanced benefit, even if he doesn’t meet the prerequisites.
Advanced Benefit: When wielding a longsword and a shield, if an opponent scores a critical hit against you, a number of times per day equal to your Wisdom modifier you may use an opportunity attack to counter it with a shield bash. If your attack roll is higher than your opponent’s, you only suffer normal damage, and the opponent’s weapon assumes the broken quality.