Hi Twistandshout,
I've heard many theories over the years:
Cost, the old Full Floater had a lot of parts and would have been expensive to produce. It is also a costly system to maintain as it has so many bearings [and they had to be kept within tolerance as the bearing play multiplied in the system].
Marketing, all the other manufacturers were using the same basic layout. Suzuki and Kawasaki were the last to follow.
Some people claim better mass centralisation [lower polar moment of intertia]. I reckon it wouldn't make much difference.
There are probably many other theories, but the reality was it took them many years to build a system that worked as well. And the funny thing with Suzuki was they went from the best rear suspension to the worst in one model year - the '86 model rear suspension was a complete dog. History has shown that the marketing people had more power to influence bike design than the riders or engineers.
As for the theory of compressing the shock from both end being a good one. Yeah it is. It has lots of benefits [many of them nothing to do with suspension quality]. Ducati still use a variation on the system on their Superbikes and Honda has used the concept on their MotoGP bikes as late as last year.
Long live the original Full Floater.
VMX42