Not only makes for an ugly tv ship, it's an absurd concept:
The fact that that the rear section is called "stardrive" implies the front section is not the stardrive so the saucer can't go at warp speeds (which was already evident because it has no nacelles, what, according to treknology up to -- or since-- Cochrane's Phoenix, are what makes the ship go to warp).
And if the battle section goes into battle (duh) and is destroyed or disabled, the remainig womens an chidren remain stranded in deep space in their slower-than-light lifeboat forever.
The same thing applies to lifeboats in general. They're not really intended to be starships in their own right, but emergency craft for survivors/evacuees until a rescue ship arrives. What happened at the end of Generations
--with the deployment of various ships to Veridian III--was really a text book example of a rescue operation (it could occur either on a planetary surface or in deep space), IMO.
To be fair, the saucer has enough long-range communications ability that it's unlikely they'd be stranded forever. Just until another ship could get to them. Even if the saucer didn't have the capability for such communication on its own (unlikely), at that point I think it would be standard procedure to send a communique to Starfleet when the decision was made to separate the saucer.