You can demean little jimmy for not wanting to play big scary islanders, or you can be proactive and try and remove barriers to parents thinking about playing the sport.
You over complicate the grading process.
If you have 100 kids, you have 100 kids. For every 12yo that has to play up, there will be an 11 yo that also plays up in the 12's.
Zero sum game.
I'm not demeaning, but if jimmy or his parents have a problem it is THEIR problem, don't make your issue everyone else's. If jimmy is too small he moves to another grade, not the big kid, because the majority of parents and kids don't care about the big kid being there.
It's a complicated thing you're suggesting, one club could have a team with a bigger than average front row, boom grading happens they all go up and suddenly they don't have a front row, the the team below has all normal sized kids so none of them qualify/want to move up. Works well doesn't it
Look at what happened to the poor kid last weekend, no longer playing because of other people's issues is that just as bad, if not worse than a small kid not playing because of getting belted by bigger kids? And don't come back with "if he was graded in weight we wouldn't have this problem" if that kid was graded on weight he'd probably end up in the u12's and then we'd have the problems I've outlined previously. Moving him up from the u8's to the u9's wouldn't have done crap