Weathering etc does not necessarily add to, or detract from, the overall model, and is not, in general, one of the points judges are looking for.
There are a multitude of models, across the world, that may have won competitions, but some, or in fact many, look like very good models, but not like the real thing as portrayed, due to, let's say "over enthusiastic" weathering, and especially panel-line work. Many of these have been built, and judged by, those who have limited knowledge of the subject, or aviation in general, which is not intended as a slur against said groups, but is a fairly common trend in any "enthusiast interest area", be it aviation, cars, modelling or whatever.
Weathering is a subtle art and, although it may add to the visual appeal of a finished model, is not, in itself, a necessity, but more of a cosmetic ( or perhaps historically accurate ? ) "bonus".
There is nothing wrong with depicting a particular aircraft as "factory fresh" ( as it would have been, at some point ), given that the colours are at least fairly accurate, and the overall finish "looks right".
The main thing is to have a clean and tidy build, with all geometry correct, and a good paint and decal finish - weathering, and exhaust stains etc, can come later, but should be based on evidence of the actual aircraft being modelled., whenever possible.
