You bring up and excellent point about more than 2 color pattern, Bob......
I think because as we were learning we were taught to make an excellent showa you take an excellent kohaku pattern and overlay it with black in the right places, this creates the problem we have in this sutuation. While initially the advice is not wrong, it creates a fault or weakness in our own thinking.
As we progress in the hobby I would hope we would lean more towards the understanding of dividing the koi into thirds. The head shoulder pattern. The middle, and the tail. Ideally we would want in the case of a showa, the three colors in each area. But balance and pattern also contribute. For example.
Imagine a kohaku with kuchibeni and the last tail pattern that runs flat up to the tail with no white "tail stop". The pattern itself is balanced. Now take a showa with a black button nose and an inazuma black pattern that runs into the tail stop. The last third has a bit of red from the middle section slipping into it's leading edge and startling white in between.
While we would prefer to have a red pattern 2 cm tail stop, the last third area has the needed ingredients to compete. 3 colors. varied and interesting pattern and it's balanced. In other words the pattern is there, it's just not the red we were taught to expect. I think some times it might help for understanding to be color blind. You could see the pattern and not be influenced by the color.
I think I would rather own for my own enjoyment a unique koi that catches your eye with an unconventional pattern and a presence about it, then a "bread and butter" that's techically correct but has no pzazz! (maybe it's what drives Guys over 50 to drive little red sports cars instead of a luxury limo in a black or silver grey.)
and i'm sure the auto makers will continue to make sports cars and limos, just as the breeders will offer the cookie cutter along with the unique.
An old friend put it in perspective one day when following a show, he didn't take GC. "You know,Dick.....This koi gives we joy 363 days of the year when I see it in my back yard everyday. The other 2 days it's at the show is up to the the Judges and the folks viewing it to decide." I think he made a very good point.