Good points.
I don't personally think 3 heats in 5 days hurts top class 800 guys - I think it actually rounds them nicely into shape - the right blood profiles, muscle tension etc.
The drafting point is interesting though having seen Rudisha in London I have really come to question that when climactic conditions are right (no appreciable head winds) that over a short distance like the 800m the benefits of pacemaking actually even out with the problems pacemaking creates. In London Rudisha was able to run exactly the race he wanted to with an open track ahead of him and the results showed.
We talk all the time about the benefits of pacemaking but surely there are even small problems it can create that who really knows how it affects an optimum performance.
To my previous point there has to be an absolute optimum pace and effort to run each 100m segment in order to reach the limit of human performance or lets even say to run 1.39.9. In this regard a pacemaker needs to almost identically match those levels of the candidate he is pacing. In a 1.44 race it doesn't really mean a lot - the margin for error is large. In a potential 1.39 race that margin for error in non existent. So even with the benefits of say minor wind shielding and the mental aspect of running on a shoulder it could be undone with deviation from the absolute perfect speed and effort distribution and also from even visual cues like beginning to decelerate as the pacemaking job is finishing (usually around 550-600m)- it's more complex then we even know.
Certainly Rudisha doesnt really appear to benefit from pacemaking as his favorite pacemaker Sammy Tangui is actually one of the worst pacemakers I have ever seen in my life - running most times 3-5 meters clear to 430-50 meters and appearing to struggle as he does so. Rudisha never looked so good and powerful as he did when he had an open track in front of him in London and just his own pace judgement to deal with