Feat: Skill Mastery

Prereq: None.
Benefit: Choose any one skill and choose from two of the benefits below -
Gain a +4 bonus to all skill checks for that skill.
The skill is always considered a class skill for you.
Your maximum rank with the skill is increased by 3 (to your level + 6).
Once per session you may re-roll a failed skill check with that skill.
Your threat range with the skill increases from 20 to 19-20.
You may permanently change the ability score that your feat uses as a bonus to be either Int, Wis or Cha for the purpose of your character using the skill.
When spending action dice to increase your skill check roll, you roll and add double the number of action dice to your result.
Special: The first time this feat is chosen you automatically get the action dice benefit in addition to two others. You may take this feat multiple times, each time it applies to a different chosen skill. The feat may be used instead of a skill based feat that is a prestige class prerequisite or a bonus feat from a class ability.


Some of the reasoning behind the idea

All my d20 books have a collection of feats that give a bonus to one or more skills. Rather then have all these slightly different skills I thought it was more elegant to have a small number of generic skill based feats (of which this is one). It would have been nice if a d20 publisher did this for me, but (grumble, grumble) generic reusable components obviously don't help them sell more books.

As a feat this is probably slightly over powered. I don't have a problem with that given I'm trying to encourage players to make good use of skills and take some non combat feats. I'll also be using it with NPCs and monsters in the game.