Grades are important, they let you know how you're getting along and serve as markers for improvement, they represent a great challenge as you strive to become a more efficient and stronger climber, it doesn't make you a 'grade whore' because you want to achieve the next level of proficiency, on the contrary, it means you are a passionate ambitious boulderer. After all the hard work, learning and training, it's O.K to every once in a while be proud, give yourself a pat on the back and think ''I'm a bad ass 7A climbing motha fuckah !!''
It's not that hard to come to a concensus, people should know their own size and their own strengths and weaknesses, they should be able to realise when a problem would be slightly harder for someone with a smaller reach or less campus power etc.
I have only bouldered to 6c+ in Ireland here are my proposed benchmarks ...
Technical Benchmarks Power Benchmarks
5 Original route 5 Rising Traverse on Big Jim steep side
5+ Smear test 5+
6a Arete on the fin 6a Big Foot
6a+ St. Kevin's Slab 6a+ Squamish
6b The Plum 6b White Arrow
6b+ Arete Right Of The Fin 6b+ Duffy's Slap
6c Chillax
6c+ Barry's Problem
I know climbers who would cruise the technical list but flail hard on the power list, they should realise that they are weak and that some training would get them up to speed on power problems, vice versa I know beasts with shit technique who do well on the power list, but make a holy show of themselves at the technical stuff, they should know their weakness and adjust their internal 'gradometer' before giving their opinion on the grade.
When it comes to morpho / reachy problems they should be graded by how they feel for people of average size and indicated as morpho in the given guide, this way a tall person can assume the problem may be an easy tick for them, small people and youngsters can expect a bit of a fight / impossibilty.
... and remember folks ''tall people reach things, small people climb things''