I don't see why it's sad they kept it rear motor, the B4 has been the benchmark chassis to beat on low to medium bite from club level way up to the pro's - and I can't think of a chassis that's been copied so many times or used so many times as a donor car for prototypes. It is just that good! The only thing it has going against it (in mainland Europe) is the fact that it's not metric!
Also I recall Yokomo has a tight connection with Associated, right?
And if I understand it right, the new mid Yokomo (as run on the EOS) is to replace the rear-motor Yokomo entirely... Could it be that Yokomo in the future will be marketed as the mid-motor brand and AE as the rear-motor brand... To keep them from competing each other to death, or perhaps put in better words, to allow for space for Yokomo to gain ground in Europe?