If there were some new little-known PED being used, you have to ask why we haven't seen similar break throughs in longer track races. Reality is that nobody is coming close to the current records on the track. This is plausible evidence for the "marathon is where the money's at" argument.
The Olympics seem like a joke when only three Kenyans can run, given that they have 6 or 7 men who are 2:05 or faster.
The "Kenyans ought to have more than 3 entries" doesn't make any sense to me in the context of a competition between nations. This is hardly the first time in the history of the Olympics that one country or another has had overwhelming dominance in an event. From the perspective of promoting this or any other sport I can't think of anything more damaging than reducing the chances of an underdog making the podium.