Yes. Assuming laws and provisions could be homogenised, then yes. The basic model would be a combined UK/France/Germany system, with the other countries having to adopt the systems they have rather than vice versa. For example, an EU-wide health system would be modelled on the current UK/France one.
But I don't think radical, immediate change should happen. The EU should carry on passing laws that increase its power over national governments, and transfer power from the Council of the EU to the EU Parliament so that the ultimate power resides in a Union-wide elected body. Then the process of adopting joint laws would begin and countries would refer increasingly to shared law and practices rather than national ones. Finally, the national governments would be reorganised underneath the EU Parliament similar to current devolved parliaments in Scotland and Wales are under the UK one. I think taxes would be operated independently by local, national ("state") and Union ("federal") treasuries.







