He recovers and catches his foe off guard... (PEACH)

[Vhaidara]

FEAT
Backhand Slash
Prerequisites: BAB +6
Benefit: If you roll a naturaul 1 on your first attack, but would have hit if 1 wasn't an auto-miss, then your next attack either catches the enemy flat-footed, or gets a +5 to hit, at DM's discretion.

Main Question: Should this be a skill trick with slieght of hand prereqisite ranks?

[Hazkali]

I don't quite know how skill tricks work (not having Complete Scoundrel) so I couldn't say whether this should be a feat or trick.

However, if this was a feat I would definitley remove the "DM's discretion", and make it always one of the two options, and clarify the benefit description.

The feat seems okay in terms of balance, if a little on the weak side. By the time your attack bonuses are auto-hitting, the next attack probably has a fair chance of wiping out the enemy with or without the flat footedness. Personally I would change it to "if the first attack misses", with beefed up prerequisites, so:

Backhand Slash [General]
Prerequisites: BAB +8, Dex 15
Benefit: If the first attack of a full-attack action fails, the target of the first attack counts as flat footed for the second attack of the action.
This feat may be taken as a fighter bonus feat.

But that's just my two groats.