When Mode S becomes mandatory any non-Mode S aircraft will be refused entry into CAS. With or without any further changes to CAS the Central Belt is difficult to pass VFR at anything other than a narrow corridoor at low-level, or alternatively flying far-out over the East, either of which can be impractical. With mandatory Mode S this will make things worse.
The airspace setup in the Central Belt is awkward, nonsensical and archaic (much like elsewhere in the country - London, Manchester...) and yet it still continues to sprawl uncontrollably like some sort of horiffic cancerous growth. There seems to be little effort made to reconstruct airspace, merely to continue patching it up willy-nilly making it messier and messier. The Half-Mil charts are an eyesore with various bizarre shapes, different classes, different bases, transition altitudes all adjacent to each other... and this organised confusion is meant to be for "safety"?
I hear you're having a spot of bother with EFPS FBW...
Smithy