My sympathy goes to the organisers for a very difficult and thankless task. Constructive critiscm maybe, but it's much more difficult to propose solutions or offer to help. There are very few decent G scale layouts about, no one seems to build new ones and in my view the standard of them is generally poor, so maybe by widening the scope it is possible to find something new. Traders will only go if visitors buy something while they are there and there are now quite a few garden rail shows during the year competing for business.
A good point about the traders, but traders of, predominately, one scale do not really like going to shows that are 'not a definite market'.
If a show is multi-scale, and they are a trader who does deal in multi-scale (online or with a physical outlet), they have to decide how much of each scale stock to load the van with.
If they are only, or mainly, a G scale trader, having a stand at a show which is a 'multi-scale' show, maybe puts them at a disadvantage as the number of public attendees looking for one scale will be less than a show whose only purpose is perusing G scale..
From our perspective as G scalers, if traders only have a smaller selection of G scale on display because space is also taken up with other scales on their stand, then we have a smaller choice to peruse from that stand etc etc etc.
Having said this, the best show that I have attended, in my experience was the combined G scale Society and ALSRM (Association of Large Scale Modellers) at Reading back about 10 years ago or so. It was large, and although 'multiscale' it had plenty of G scale layouts and traders, but it also had the buzz of there being 'other stuff' to look at as well.
My main beef with the recent G-Rail shows, is not only the seeming lack of 'live steam' layouts and traders, (which to be fair has always been the case), but also was amazing lack of modelling stands that have tools and equipment for modelling on sale. There used to be a good number of them in the past.
The Midlands Garden railway show, outside Leamington Spa, always has a good selection of 'equipment, tools and materials' stands as well a good representation of G scale and live steam stands.
Perhaps the 'embattled' organisers of G-Rail should look at other shows and use what parts of those shows make them a success and then emulate them..... just sayin'