Bob, a common theme runs thru all the 3 or 4 (who's counting? ) reasons you list for immediate deletions with the CoB model: all benefit of doubt is taken from the posters' hands and placed squarely in the CoB's which insinuates an element of distrust on the part of your community of posters. It also empowers the CoB to use their thread as a personal soapbox as Jenna as so aptly demonstrated - as recently as a couple hours ago by canning innocent posts (albeit probably off topic) by bob_john while NOT deleting her own off-topic pokes at him.
The timeliness issue cuts both ways. What if there is important news regarding a stock pick that cuts against the CoB's position (ie bullish news on a bearish position)? I can imagine many other scenarios as I'm sure you could w/ respect to deleting posts right away or not, so in my mind it boils down to trusting your community or not and (right now) my perception is that you do not.