So Scotland and Wales would get elected assemblies. And England would get a large Commons Committee. Scotland and Wales get First Ministers. England gets jumped up MPs. And you can be sure that England's MPs will want extra reward for their doubled up role.
The only way for equal treatment for the voters of England would be to set up a separate directly elected English Parliament with the same powers and responsibilities of the other assemblies. And before the complaints about more politicians, I would say that, with four national bodies, you would not need so many MPs - so they could be reduced by 80% or so and discuss Union issues only.
Full equality for England should be just that - no more and no less - and without giving England what the other nations have, then equality and fairness will not be achieved.