The stated reason for Hall running London last year was to fly under the radar. That would seem to go against the idea that finishing well at London would result in more attention than running well at Boston.
As for what the average person sees and hears, all I can say is that, whenever an American finishes in the top 5 at Boston, at least a couple of people at work are asking me about that. I haven't heard a word about Hall's performance in London at work. Maybe that's because Boston results actually make a couple of the local papers. I don't think I've ever seen any London results anywhere in the local media and I question whether even running an AR or winning would get an American in the local media if it was accomplished in London.