Well the saucer separation was primarily advertised so that the civilians could run away when the Enterprise had to go into battle.
As the years went on, Picard began to think, fuck it, if the civilians and children didn't want to be on my ship, they wouldn't be on my ship.
Was the Enterprise more or less powerful without the Saucer?
Less surface area meant the shields would be much stronger if the powersupply remained constant.
Less mass meant it was faster.
The saucer section just seems like a burden in times of war.