I ran my first session of the playtest last night and after mulling over it today I still think it is too much.
Whether the player succeeds for fails, it really doesn't matter, every other PC will benefit from the dropped AC of the creature. During the session, it was driving me bananas trying to keep track of the flat footed condition on all these creatures, and it was essentially a free -2 AC debuff.
In my opinion, I think the failure should result in just no effect. You try to grab someone, and you don't. You try to attack and you miss, you don't get to make them flat-footed and you don't get to hit, respectively.
Has anyone else dealt with this fighter feat?