Salutations,
This feet has been a write off in our group.
As I look at it, I think it is too weak for any use. I can't see it ever being taken. Anyone with that wis is most likely a caster- and would be better off taking a feat that helped their magic.
So, there are three options-
1) If one raises the BAB and get rid of the Wis requirement, then the feat is probably fine the way it is written.
2) If one raises the BAB and keeps the Wis requirement, then make the feat change to: opponents who flank a character with this feat gain no benefit from flanking(bonus to hit, sneak attacks, etc). Keep the bit about it only working while not denied their dex.
Since the second proposal is rather powerful, I think the BAB requirement should be at least around 13+
3) If one keeps the BAB requirement and gets rid of the Wis requirement, then you could change the feat to the following: at the beginning of each combat round, a character with this feat may select a number of people equal to their Wis bonus that will not receive any bonus to hit gained from flanking this character for the rest of the round.
I like #2 just because there are so few high level feat for combat, but I would go for #3. It is geared for combatants and rewards a decent wisdom.
Respectfully submitted
FD