I do tend to agree with some of John’s comments in that I think Expo should be a showcase for EM gauge layouts, rather than P4, as a significant part of its raison d’etre is to demonstrate that finescale modelling is within the reach of most modellers. I do admire those who can model successfully to P4 standards (and have been privileged to see Semley in action – awe inspiring!) but am aware I am a mere bodger.
For me, EM standards provide a good compromise; sufficiently close to total scale to deceive my eyes, yet with sufficient tolerances to cope with my ham fistedness. I think we should celebrate that pragmatism. It would be a shame to lose Expo; maybe we should regard it partly as a marketing cost to showcase EM (but again, that would require EM layouts, not P4…).