Gaffer Tape said:
It probably would have required them to get too close to the moon to keep from being detected. The whole plan was based on the element of surprise. As soon as the Imperials realized that their shield generator had suddenly been blown up... BAM, the entire Rebel fleet shows up at their unprotected doorstep.

How much time would it take? The entire Rebel fleet suddenly shows up at the Death Star’s doorstep, for 15 seconds they throw everything they’ve got at the site of the shield generator, then they turn their attention to the Death Star. It would be a hell of a lot faster than a ground assault.

If, for some reason I can’t imagine, you’re committed to a ground attack, you don’t need an entire assault force equipped with plastic explosives. One martyr (or, for that matter, a droid) equipped with one really BIG bomb would do the trick. We don’t have to be talking Chicxulub here. Winslow Arizona would do the trick. Surely the Alliance has that level of technology.

Come to think of it, a single space cruiser flying at relativistic speed into the planet would pack a hell of a lot more bang than the Chicxulub impactor. It would pulverize the planet on impact. Why did they need the Death Star for the power to destroy a planet? If they had the technology to move a large vessel at lightspeed, they already had the technology to destroy a planet.