Honestly, I think grazing is a retarded scoring element, and I see it as a lack of creativity on ZUN's part in all of the games aside from SA, where grazing is the whole point of the entire game. Pretty much every other shmup out there has nothing to do with grazing.
Well, there are Radiant Silvergun, Raiden Fighters series, Psyvariar series (superb games, btw), Shikigami no Shiro series, DoDonPachi 2: Bee Storm, and a good number of doujins, among others. Not a selection I'd easily dismiss.
Besides, I don't consider grazing a bad element of scoring system. It's great to excercise risk and reward tradeoffs, and it brings really high tension to scoring at every part of a scoring run. It's really only bad when you're required to milk bosses for every bit of graze for a long time, or when you only get to graze anything easily dodgeable or while under an invulnerability effect most of the time. I think PCB and IN are by far best grazing implementations in a scoring system among Touhou games, and those are coincidentally less focused on graze milking compared to every other Windows Touhou game with a graze counter. See the pattern?
Graze-related. This is the major one.
For some reason I think something is wrong with the last statement there. I don't believe the game generates anywhere over 30000 bullets during the time of a single bomb explosion, while the score increases indicate exactly that. I think the value increases for each subsequent bullet canceled, or akin to Raizing medal progression (every medal on the screen is generated with the same value until you take one of them). That's why the bonuses aren't half as big when you're canceling only half the bullets the WR players do. It's not linear.