Walking/pushing has a long and honourable history as part of UK mountain biking.
The good thing is that there is a format for everyone:
Riding over technical terrain without dabbing - Trials
Technical speed downwards without need for speed upward - DH
Rally style events - Kona Mashup
All round riding - Singletrack Weekender
etc.
etc.
XC racing has got to where it is today through a process of evolution. Personally, I like technical tracks (Inners BUSAs track was pretty sweet) but I think that there is space for many types of track, its impossible to define the perfect track and every single one will be a different balance between the a wide range of factors including but not limited to skill, fitness, tactics, bottle, equipment choice and preparation. In a very real sense though, since they are the springboard to larger events and eventually World Cups, World Champs and the Olympics, they have to reflect the design and philosophy of the global scene, for better or worse.
Most events in this country are run under the auspices of BC. When BC officials assess a track it has to be primarily safe and fair, distance and other factors also have to be considered however the first two are paramount. Usually the same track will be used for all races so it has to be suitable for all riders especially the younger ones and not just the testoterone fuelled weekend warriors. This does leave a large amount of leeway but usually rules out doubles, large drops and the like.
As for comments about marshals, marshalling is (as I suspect many of the contributers to this thread know) often a tedious and thankless task, if more racers volunteered occasionally both the quantity and standard of marshalling improve it would help organisers hugely.