Sorry but that does not make sense. You could the say the same about any jurisdiction. Who would want the UK to go back to the laws they had 100 years ago? Things change the UK will change it's laws in the future as will the EU.
Think about it
Votes for Women,
Scottish Goverment,
Welsh Goverment,
Good Friday agreement
Mayors,
and no end of other major constitutional changes.
Remain IS a clearly defined position at this moment in time. If the EU want to make more changes to their constitution then it will be debated by Council of Ministers and the EU Parliment, to gain a consensus for the change.