>>23367498
The idea of imitating 2D painting on a 3D object is also just not as common in gunpla or scale modeling in general as it is in miniature painting. There's a reason why weathering is considered the only real creative step in the modeling process by most modelers, and since doing extensive weathering on small scale anime robots is rather difficult...
So rather than the paintjob, most self expression in Gunpla comes from customizing proportions and detailing. It's just the natural conclusion.