Register office weddings can be over in minutes. I know people that have gone and done it in jeans, in their lunch hours, and then gone back to their desk. It only needs formality and ceremony if YOU want it. You don't have to be Mrs. You don't have to change your name. I didn't.
They certainly should close up the differences between marriage and civil partnerships - eg if mothers profession is not on the marriage certificate, they need to update the certificates! (I thought they were planning to do this anyway - genealogists have been lobbying for it to happen, certainly).
Once those things are changed, what real difference between marriage and civil partnership except in people's minds? To me, a civil marriage with no religious content in a register office has no connotations of patriarchy, to others it evidently still does.
One thing I would like to lobby for is for humanist celebrants to be able to conduct civil weddings - in England and Wales (as far as I know), if you want a humanist ceremony you still have to have the register office official ceremony too. I didn't see the point of having two ceremonies so we just had the basic register office do, but if I could have had a humanist wedding, I would have loved that.