David Poile did not draft Scott Stevens.
In June 1982 the prior GM drafted Stevens - it may have been the interim GM Roger Crozier but I am guessing on that one. Anyway, then in September 1982, Poile was hired as GM either right before or during training camp. Five days later he traded Green and Walter for Langway, Englbom, Jarvis and Laughlin.
I thought Poile was very good generally at the draft in his early years with the Caps and then again in 1993 (getting Witt and Allison), but was very poor through most of the 1990s until he was fired. Toward the end he had a string of first rounders who never panned out. I remember late in the 1990s ESPN stated during a telecast that the Caps were worst in first round drafting, with something like only 4 out of 15 first rounders having made it to the NHL.
I thought he was also very good in trading, particularly getting Larry Murphy and Dave Christian for very little, but once again his trading seemed to not be as good in the mid to later 1990s.
As far as letting Stevens go, I think Poile would have kept Stevens if money was not an issue, but due to Pollin's tight purse-strings Poile had to convince Pollin that it made financial sense, and I remember Poile later saying in print in an article done by Dave Fay of the Wash Times that if he had to do it all over again he would have kept Stevens but at the time he did not think that salaries would escalate so quickly and so much right after the Stevens deal with the Blues.
Speaking of Pollin and money, I remember the Post reporting that Pollin nixed a Poile deal that would have been Selanne for Allison, Cote and Baumgartner due to the amount of Selanne's salary.