I guess the solution is left to the pilots. Fly the sequence or pattern perfectly and the judges won't have anything to mark you down for.
I'm not sure what you mean by deviations from scale but, all "scale" models have deviations from the prototype due to size. You can't soak a prototype in hot water to shrink it to a smaller size and expect it to fly well. The size of the plane makes difference in design.
I like IMAC & SPA because of the people involved. We compete but, have a bunch of fun while doing it. So, competing in both venues allows me to have twice as much fun.
As for judging ...someone has to do it and if you're going to compete you should be ready to step in to the judges seat once in a while. Remember, no judges, no contest. Besides, learning the rules well enough to judge will make you a better pilot because you will know what they are looking for. Some errors have a greater deduction than others and that may be where some of the perceived judging errors come from. Some errors count 1/2 point off while others are a full point off. Check the rules and you'll see what I'm talking about.
Take care and God Bless,