I think if attempts at changes were made to benefit both sides in a shared care situation, we would get an outcry of 'vulnerability' claims from the children's charities, women's charities and possibly also the think tanks that deal in social equality issues.
The simple fact of the matter is that women earn less than men, despite legislation that makes it 'illegal' for doing the same work that men do. Women are most likely to be in lower paid work, particularly in caring professions and where they are in higher paid work, will have probably missed out on promotion opportunities as a result of taking maternity leave and/or going part-time for a period. And whether we like it or not, it is usually the mum that children end up living with when relationships breakdown. So even in a shared care situation, it is more than likely that mum will be worse off financially than dad in a 'pound in the bank account' way.
For these reasons, I think the few situations that arise where shared care is genuine (and many of you know what I think about 'genuine' shared care as opposed to 'reducing maintenance liability' shared care!) and the non-resident parent (in
child maintenance terms) is earning less than the parent in receipt of child benefit (the 'trigger' to be able to claim through the CSA), it is unlikely that you would ever get a Government to legislate from a financial perspective in favour of 'shared care = no maintenance'.
Of course, what we could go back to is legislation that takes into account, at some level, individual circumstances by the CSA. I think, however, that most NRPs who pay on this system still (and there are a good number of them out there) would much prefer to be on the post 2003 system that we have now (straight percentages of income).
The biggest issue is that we all see our financial situations from our own perspectives and struggle to understand why we should fit into the 'one size fits all model'. Unfortunately, a Government really only can legislate for 'one size fits all' which means there will always be very obvious winners and losers. I suspect that for most of us, however, the system works well enough.