Thanks for your reply. Your question is important and so I want to address it properly. However, if I am misinterpreting it please let me know.
You mention NYC and Berlin. These races can be hugely influential towards qualifying for Boston as they are very large and they generate many BQ's. Berlin, especially, because the course is flat and fast. It typically is one of the top 5 qualifiers for placing runners in Boston.
NYC's course is much harder than Berlin. It typically does not place in the top 5 for entries into Boston.
Yet both of these races do have many "elite" runners in them. However, I don't think the presence of elites in these races make much of a difference in qualifying for Boston. The elite fields are typically invitational and don't subtract from the number of qualifiers that Boston will accept.
It is true that the other races that you mention (REVELs, St. George, Erie) are geared for runners like you and I who are borderline BQ runners. This brings up "Utilization Rate" (UR), the term I use to describe how many BQ'd runners from a qualifier actually use their BQ to apply for Boston. These races tend to have a high UR (30 - 75%) because many people run them for the purpose of getting into Boston. UR's for Berlin and NYC are much lower (<20%).
Also, I have found that very fast runners (semi-elite) tend to have a lower UR than runners very close to the qualification standards. Thus these fast runners don't influence the cutoff time as much as the borderline runners do.
If you have not already read them, I would suggest you look at my posts from Sept 6 and June 7 wherein I discuss these topics in depth.