I don't put much stock in fielding pct. It doesn't account for range.
I don't think that the Hall should be made up of only outfielders and 1st baseman, who are generally the players that put up bigger career numbers offensively. Is Santo As good as Robinson, Brett, or Schmidt? No, but so what?
I keep going back to this... If a player is dominant at his position for a decade, as Santo was, he should go into the Hall.
Based upon that, I would agree with you. My biggest problem with the HOF is that even though some players were the dominant person, they were clearly not the best of the best all time. I.e., Bill Freehan. Absolutely no way should he be in the HOF. Santo's numbers, I concede, I borderline. Freehan's are nowhere near other catcher's numbers (and the same goes for Bresnahan, Schalk, and even Lombardi).
The HOF is for the best, not just for the good. Dickey, Berra, Campanella, Fisk, and Gary Carter all match up to players at other positions. That's my criteria. Otherwise, you get players who really don't belong, IMHO.