i have found that too, a_in_the_ab, and i think what we are saying is not at all at odds :) there are a lot of factors that go into everything. with 3 point shooting, and guard shooting in general, per, spd, iq, ath, bh (not in that order) are all pretty significant factors. yet, you can have a very effective scorer, and a surprisingly effective 3 point shooter, even without good per, which i think most would agree is easily the #1 attribute for 3 point shooting. so, i think a high ath/per guy could most certainly be a very effective 3 point shooter without great speed, or with great speed and without great bh, etc.
also, ratings are all relative. so, when you say you played the guy at sf, for his opponents, good spd for a guard may become great speed, for all intensive purposes. many of my most effective scorers are true guards, playing at the 3, for the same reason (all ratings are relative to the opponents).