I completely get that it is as clear as mud. What i often find when a customer comes in and says 'i'm after a grade one bat' is that they don't have any answer at all when i say 'what's your definition of a G1?'
It's been discussed at length in the past, the simple grading system of 1-5 is pretty pointless. There is more than one willow merchant, each merchant having their own grading criteria, with no industry wide regulation/monitoring, there are at least 14 different grades available to buy from merchants as far as i'm aware, how that translates into grades 1,2,3,4 and 5 is anyones guess. Some brands/batmakers regrade as they see fit when they take delivery of the clefts. Some brands/batmakers fell their own willow. Some clefts are now graded on size/density, see the reasonably ugly Warner bats for $1000 AUS for further details.
There are also things like G1+ and 'Pro' grade to consider too.
Most of the major manufacturers no longer explicitly state the 'bat x is grade x'
I appreciate it's impossible to correlate everyone's expectations into a simple grading system. Can't we just have a Freemason style secret grading system? So when people come into the store we can have a secret handshake then say I'd like a:
Low density - Can have between 1 and 100 grains, this is a science experiment not a grade.
G1+ - Blemish free, perfect white Willow. Grains are too subjective.
G1 - A small blemish on the face, not in the playing area. Or a perfect face with heartwood
G2 - A few blemishes, perhaps some graping. Heartwood almost guaranteed.
G3 - An ugly face, or butterfly.
G4 - You're asked to leave the store - "Sports direct is over there" *Points towards the door*
G5 - "B&Q sell MDF, I'd try them." *Speak slowly, it may help*