Unfortunately, there are always winners and losers when it comes to those near the criteria threshold. You'll never change that, it's the nature of most policies and schemes.Some sort of NI contribution per year scheme? Perhaps.
But the problem with trying that sort of 'exception' approach is that there will be a million different edge cases where someone who has done everything right will get ignored. Plus making sure people actually get it and can navigate yet another form.
Separate to that is that you're still punishing children for their parents choices and actions.
However, I still don't agree with the principal of people producing more and more children that they can't financially support.