All good points mate.
I personally found Stanta incredibly annoying to operate in....mainly because I believed the chart and the FL50 restriction (serious point - I have no reason to doubt you but if given the choice between a AIDU product and 'some bloke off t'internet'....I'll go with the chart!), but also because of the comms required to operate in the Lakenheath approach lane. I never really achieved much at Muckleburgh either really.
Best CAS I did in the UK was ivo Lampeter...but that did require the brown jobs actually going somewhere different - which may or may not be practical for formation work ups. So maybe we are stuck with SPTA etc. (Which was always a pain because you only ever got one of the three 'chunks' and had class A stuff north and east from memory, and low level was tricky.)
Your points on sensor use and medium level deliveries are all valid.
Don't know why we're discussing this really - hardly up to us is it?