Quote Originally Posted by Fruchtkracher View Post
Seeing how we already have a feat in the original Complete Scoundrel that let's us reroll any failed save a feat for either a fortitude, reflex or will save seems kinda weak...
Sure, the original could only be taken at level 9 or later, but perhaps you could add a +2 or +3 bonus to the reroll.
Hmm. Although I agree with your point, the non-prerequisite luck feats in Complete Scoundrel that are first available to player quite consistently grant a lesser version of a higher level luck feat (such as any of the luck feats that grant the ability to reroll 3 specific kinds of skill checks compared to the higher version that simply allows for the rerolling of any skill check). Due to this, I try to keep the power of homebrewed luck feats that lack any prerequisite equal to those of the other non-prerequisite luck feats.

Quote Originally Posted by Fruchtkracher View Post
Lucky guess would be more usefull - and it would fit in flavour - if you ccould guess wildly on untrained knowledge checks, perhaps in exchange for one luck reroll spent.
At first I thought that allowing the rerolling of any Knowledge skill would be too powerful in comparison to the other skill check oriented luck rerolls. After your comment, however, I am thinking you have a point there.

Quote Originally Posted by Fruchtkracher View Post
Serendipity is just weak. +1 to AC if you do not use all of your precious rerolls?
I'd increase the AC bonus as you either gain more levels or better yet more luck rerolls, and/or add a save bonus to it =)
I think I will keep this one the same for a very simple reason: it is one of the more character-friendly and down-right stronger luck feats in the bunch. Not only does it grant a +1 bonus to AC (such as that granted by Improved Natural Armor), but the bonus is a luck bonus that applies to all armor classes, regardless of circumstance. In addition, it grants two luck rerolls, which are like gold to a luck-based character.