Flying Crane
Sr. Grandmaster
I don't go by length or complexity unless it is in the same belt catergory.
If I'm grading Orange belts and below and everyone does similar katas, even competitors outside of the dominant system presented will have similar techniques in their forms but one has a slightly longer form or it has more complexity to it (Orange belt form instead of White or Yellow belt level) than the more complicated form gets the nod all things considered equal.
I see the point you are making and it does make sense.
However, this can't by applied in every situation. Many Chinese arts don't use a belt system to begin with, and they often have a much more nebulous distiction between where a form lies in the curriculum. For example: the very second form that I learned in Tibetan White Crane, was something I started learning after maybe 6 months or so of training. But it is considered a cornerstone of our system. It is quite long and complex, but it includes a lot of the good techniques found in our system. In fact, if you had a good foundation in the basics, knew the first form which is just drilling of the basics, and then knew this cornerstone form, that would be PLENTY to train and become very good at Tibetan White Crane. You really don't NEED to have more than that.
So what if I competed with this form against the lower colored belts, after having been training for maybe a year and a half or less? Or I can compete with this same form 10 years later, against advanced competitors, and it is still appropriate.
How would someone with a Japanese or Korean or Okinawan or American Kenpo background react to that at a tournament? I don't know, to tell the truth, because the few tornaments that I do compete in are strictly for Chinese styles. This creates a bit more of an even playing field for this kind of issue. However, it is still very rare to have a judge who knows Tibetan White Crane, as it is a somewhat rare system. Once in a while a classmate of my sifu's will be a judge so it does happen, but not very often.
So again, I think if the systems are vastly different, it can be a real problem in judging.