In my opinion climbs should always been rated for on-sight as there are a lot of muli-pitch or alpine climbs where it’s just impossible to check out the route and memorize it. That’s why ppl usually indicate if they scored onsight or redpoint or even aided. Obviously you have to be able to score a higher graded red-point before you can on-sight the same grade. But this is part of the game as it is with protection. Again, this is not part of the grade but makes a lot of difference (traditional, heavily bolted). There are other factors like altitude, height, conditions which are not part of the grading system but which should be mentioned. I think the grade should always be as high as the hardest part of the pitch. You wouldn’t grade a consistent 20m high climb different from a 3m climb even if it’s much easier…
