imagine if the 5th class grading system had no letters and went:
4th
low 5th
5th class
5.10
5.11-5.12
5.13-5.14
5.15
except instead of using those gradations the ratings went Rock1, Rock2, Rock3, Rock4, Rock5, Rock 6, Rock7, Rock8
and no one had ever climbed a Rock 8
and holds constantly changed in size and shape, and pro disappeared and reappeared randomly, so what was Rock 2+ one week might be Rock 4 a week later....
I mean, boulder problems are the easiest things to rate in the whole world: Go from hold A to hold B and then to hold C - and people still fight about the ratings of those right? (see 8a.nu forum)