I've said it before on another thread but I'll say it again....
There are a few of us on here who have read other books and there is a specific character in one of those said books who specifically tells Hoid that he will not meddle with things. Chaos and I have been talking about it and we agree that the letter was written to this non-meddling character. We've don't want to spoil things to bad, but it is not Galladon or anyone in his published work ( I say that tongue in cheek because I haven't fully thought out if this non-meddler is a minor character that shows up as a world traveler in other books(since Brandon did say there are other characters traveling around other than Hoid.)) I hope that somewhat puts things to rest, hopefully soon we can bring more information out in the open about it or Brandon will confirm what we have asked with out him saying "that's an interesting observation" and smiling.