Amusing assessment over on the Danger Room:
From a military perspective, Hoth should have been a total debacle for the Rebel Alliance. Overconfident that they can evade Imperial surveillance, they hole up on unforgiving frigid terrain at the far end of the cosmos. Huddled into the lone Echo Base are all their major players: politically crucial Princess Leia; ace pilot Han Solo; and their game-changer, Luke Skywalker, who isn’t even a Jedi yet.
The defenses the Alliance constructed on Hoth could not be more favorable to Vader if the villain constructed them himself. The single Rebel base (!) is defended by a few artillery pieces on its north slope, protecting its main power generator. An ion cannon is its main anti-aircraft/spacecraft defense. Its outermost perimeter defense is an energy shield that can deflect Imperial laser bombardment. But the shield has two huge flaws: It can’t stop an Imperial landing force from entering the atmosphere, and it can only open in a discrete place for a limited time so the Rebels’ Ion Cannon can protect an evacuation. In essence, the Rebels built a shield that can’t keep an invader out and complicates their own escape.