Enterprise Saucer Separation speculation.

We know the Star Trek NX-01 Enterprise can't separate like the Enterprise-D could. But what if it could?

The biggest change would be the absense of a StarDrive section. Therefore the two Warp Engines would have to close together and lock in place to form one solid "Warp Ship", similar to the general design of Zefram Cochrane's original ship of having a main body and the two engines strutting out the side. Luckily, the Warp Engines are already connected to eachother with a strut behind the saucer. This would act as the hinge that would close the engines together.

Enterprise NX-01.

Saucer Separation in progress.

Warp Ship without the Saucer.

Enterprise Warp Ship.

Enterprise Saucer Section.

The galaxy can be a dangerous place. And exploring the unexplored territories and encountering brand new life that could be hostile, the emergency separation of the Saucer is an important feature. At the least the destruction of the Saucer would buy the crew time to escape home in the Warp Ship, which is capable of Warp five with the Saucer, and maybe more without.

Cochrane's Warp Ship and Enterprise Warp Ship.

This would have also provided the program with more dramatic stories. You KNOW the Enterprise will never be destroyed during the series. But if the ship could split in two, and being a proto-type first, the destruction of one section unexpectedly within a season would be incredibly dramatic. And with the replacement of the missing section to follow, more stories are created by its construction, fitting, refitting, field testing, and the fact that the replacement would be more upgraded than its predecessor module, allowing Tucker to be happy that his ideas are being implemented by the Engineers who, as the Enterprise Bible says, Tucker "has built quite a reputation with the Utopia Planitia shipyards". All of this was practical. With a mysterious villian from the future trying to destroy the Federation, his target more often than not would be the Enterprise. And with Kirk's Enterprise being so much larger, the loss of the separation option until Picard's time was also practical.

The stories that would have followed after each dramatic loss are uncountable. Think back to the field testing of the Defiant in the Gamma Quadrant ("The Search", Part 1). Think back to the refit trouble of the Enterprise in Star Trek V (KIRK: "I miss my old chair"). And the McKinley station docking of the Enterprise in "Family". And the sneak-peak of Enterprise at the Utopia Planitia yards in "Booby Trap". Imagine episodes where the Engineers would insist that after the loss of the third Saucer, they demanded to go on some of these missions to see why Archer keeps inflicting so much damage (and comedy ensues). Even Geordi LaForge said to Dr. Leah Brahms that Designer Engineers need to get on these ships in space to see them in action first hand. You can't pioneer this technology if you get it right the first time.

Warp Ship escaping the Saucer Section's explosion.

There was so much potential for so much drama and rare stories, yet sadly all thrown away on yet another franchise series with 7 immortal characters that can never be killed on an immortal starship that can never be destroyed. You don't send out your first ship into the most unknown space and actually expect it to survive intact. Unless your name is Berman or Braga.