Regional Inheritance tax allowances

It seems very unfair that whether you pay IHT or not can depend on which region you live in;some have very generous allowances, meaning you will pay zero, Murcia has recently abolished the regional allowance.
The state allowance is paltry and derisory, and would not go far against an inheritance tax of eg 200,000 euros.Surely this sort of tax should be determined at state level, with a far more generous threshold than the present one.
Another unfairness is that the survivor's own wealth is taken into account when determining the amount of IHT.
If you live in Murcia, as I do, what on earth would happen in the event of my husbands' death?