I like this option because it addresses something I’ve experienced in most 4e games, which is that certain skills are simply missing from the party (or in the hands of folks not especially well-suited to their use) and other characters are constantly rolling those skills despite lack of training, banking on the rp bonus to pull them through. For myself, this happens a lot because very few of my characters have diplomacy or bluff relative to how many of my characters give long speeches. I like to monologue, whether to deliver horrifying threats to humbled villains before I send their souls to the Abyss or to inspire the party to do something awesome like drop a bridge on a dragon. I don’t always create my characters with the expectation that they’ll do these things (though I’m starting to bow to it), but even if I did, many characters lack the necessary skills on their skill list to make this possible. See also my comments regarding Intimidation in my last language post.
I recognize that 4e already provides a few options for players to pick up skills they’re using (or that the party needs someone to use), but I feel that this option solves things more logically and attractively. Obviously, a player could simply take a feat to gain training in a skill, but I’m not sure I’ve ever seen one do so; it’s usually much more sensical to pick up a multiclass feat so you get the skill and something else. However, that’s usually a choice made at or around character creation. I have played characters who switched up their multiclass, but this was usually prompted by the publication of new books rather than seeking a different skill.
Characters can also retrain, but as someone who puts roleplaying pretty high on my list of priorities I struggle with the idea that Thog the barbarian suddenly forgot everything that he knew about nature in order to…hell, I don’t even know what else is on their skill list. You get the point. Plus, retraining still locks you into your skill list in the first place, which isn’t helpful if Thog is a Thaneborn who suddenly finds himself thrust into a leadership role and would like to be a bit more politic than just introducing everyone to his axe. The issues I’ve outlined in this paragraph also explain why I don’t view backgrounds as much of a solution.
I want the perception that players grow as they gain experience, and giving them an incremental bonus as they increase their familiarity with a skill dos this. I suppose I could have just opened up retraining to let a player replace a skill on their list, but then they’re spending their retrain for a level, still doing that forgetting thing, and there’s the loss of a sense of learning. I don’t want Thog the Face to be a silver-tongued devil immediately, but I want players to gradually grow in confidence as his skills improve.
Now, one problem that’s already been demonstrated to me by an applicant for Tinderbox is how the on-the-job training bonus combines with Bard of All Trades; so a simple “this bonus does not stack with other feat or class bonuses” probably does the trick, since it means the character will use the higher bonus until such time as On the Job surpasses it or the skill becomes trained. I don’t tend to look at interactions like that as crises, since they usually give the player additional options and expect them to make proper choices.
This is a rule I'm using in Tinderbox, and hopefully it'll spread some of the key roles (from a skill perspective) around the party's class roles.