I don't know what makes you think that BMW intended servo-abs to be some sort of "emergency brake assist" system. They never marketed it as that and I have never seen any mention of such an intention.
Emergency brake assist on cars is designed to detect heavy braking and to push retardation to the limit of grip using additional power assistance and abs and stability systems to keep it under control. But the BMW bike servo system works all the time (like a normal car servo does) and makes no distinction between light or heavy braking.
Another point - ultimate braking performance is achieved by progressive brake application to first achieve weight transfer onto the front tyre, followed by harder braking to make use of the additional grip that the weight transfer provides. Applying the brakes hard, instantly (the near vertical line for brake force against time that you mention) will serve only to overwhelm the grip and trigger the abs, thus actually increasing braking distance. No one in their right mind, least of all a major bike manufacturer, would actually set out to design a bike braking system that works in this way.
Agree with everything you wrote.
At around the time they came up with this idea I attended the inquest of a biker who had died outside my girlfriends flat on the High Road (North London). A car had pulled out in front of him, from a side road, blocking his entire side of the road, but had then stopped (it was trying to turn right) as the opposite carriageway was full (of stationary traffic). The two concepts that were decisive in the inquest's final verdict (misadventure) stuck in my head.
a)Yes the car had pulled out in front of him and had completely blocked his path - BUT, this was a 'normal' manoevre by a car driver (according to all the witnesses) and was completely acceptable because the car driver had left the biker 'enough distance to stop'.
b) The biker had failed to brake hard enough to stop, a 'reasonably competent rider' could have stopped in time (according to the Police Expert) and some special 'expert' testified that 80% of bikers (riding large bikes) didn't brake properly because they pulled the brake lever hard enough to 'just not lock the front of a 125cc bike' (because that is what they had learn't on- pre Direct Access here) but this finger pressure on a 'superbike' (in this case a Kawa Zephyr 550) would not 'brake the bike as much as a car driver pulling out in front of might reasonably expect it to.'.
Forget SMIDSY, by the end of the inquest I was surprised there wasn't a verdict of suicide.
But, around this time, there were a lot of 'studies' being cited that 'proved' that 'people' didn't brake as hard as they could have done in emergencies - which is why EBA was developed by car manufacturers, but before that BMW put the servos on to try and address the issue - once they were confident the ABS could cover those who really did know how much pressure they could apply.
I have a non servo 2001 R1150 GS and a servo 2002 R1100S.
I haven't felt the need to convert the 'S', although the only problems have been the brakes applying themselves without my input. But having said that, I don't hate BMW for trying the idea - I believe that they meant well, and I well remember the absolute slagging they got for fitting ABS to a bike (much the same as this thread: unreliable, over complex, not needed, I can do better without etc).
Personally, I will never buy another big bike with servo'd or linked brakes, but will also never buy one without ABS. But it is a very personal choice based on a very personal experience - and I believe there is no single right answer, because we are all different and our experiences will be different.
Indeed, the only thing we seem to have in common here is the need for a simple answer to the question 'which is best'?
I think it was Green who said:
'For every question there is always a simple answer,
By deffinition, it is wrong.'
). Based on all this, if i was to buy a later GS with servo that packed up, i wouldn't hesitate to remove it all. 
. In my view all was under control, no skidding, no course deviation. I stopped in good time. This was an unexpected 'incident' just like a car making the highly inconsiderate maneuver you mentioned. 
