a quick note on overall ratings:
for a pitcher, think of a "100 overall" as pitcher with the best of everything, including being a starting pitcher type who can throw 300+ innings a year (because of his combined DUR/STA) ... in other words, a combination of "quality" and "quantity," with one rating for all pitchers ... a relief-type pitcher might be of equal quality, but just not the quantity, so the best RP in the world will never be a 100 ... and most HBD ownes seem to think that the "quantity" effect on the overall rating calculation is a bit high
for a hitter, think of "100 overall" as a guy who has all the hitting ratings, all the fielding ratings, and the DUR to play 162 games ... one rating for all hitters that counts everything ... as such, a 1B/DH type probably will never be a 100, simply because he doesn't have the fielding ... but he may be the best hitter ever
so a trade of a "80 overall" pitcher for a "59 overall" hitter *could* be a trade of a high "quantity" mediocre "quality" pitcher for a DH who has amazing hitting ratings with a low-ish DUR ... it could be very possible that the hitter is more valuable to a team than the pitcher