First a quick explanation: I have not watched Rogue One yet so I'm just going by the OT.
The flaw was that it was possible to send a missile in a straight line from the surface to the main reactor. Why the death star I had that design flaw is explained in Rogue One.
The starwars fanatics have always been a bit aggravated with this obvious plot hole that the death star didn't have better protection of its main reactor core.
Hmmm… as I said, I wouldn't really consider that as an obvious plot hole. The way I see it is that the X-/Y-/Wing guidance system was programmed to lock on the vent as best as possible.
The proton torpedo probably had an advanced active guiding system so after it went into the small vent opening (the hard part), it automatically found its way to the greatest energy and/or heat emitter (= the reactor core).
I believe that you can actually see from the simplified animation when the rebel pilots are briefed about the weakness that the projectile is not moving towards the core in a straight line but that it needed to fly there in an arc.
We don't really know how *exactly* it got to the core… just that it made it there… but this would seem to be one of those parts where you have to use your imagination a little bit and imagine how the torpedo's active guidance system navigated it to the core while the DS crew was flipping switches and activating the main superlaser cannon to destroy Yavin.
I am convinced that the Empire was simply too arrogant and overconfident so they made a silly mistake (they did not realize it was a mistake at the time, of course) when they designed the first DS. You can tell in ANH that Tarkin thinks the Empire is invincible, especially after the destruction of Alderaan.
Palpatine (only a background character in ANH, of course) was also extremely arrogant and just a little too confident. Remember how he referred to the rebellion as a "pitiful little band" in RotJ?
The only person in ANH who realized the danger was Vader. He actually clashed with Tarkin a few times when they had different opinions on the significance of the rebellion. Tarkin's final mistake in underestimating the rebels was his last and fatal one while Vader lived because he anticipated the perils (with the help of the force, no doubt).
The weakness that enabled the ultimate destruction of the 1st DS was caused by the blatant overconfidence of Palpatine and Tarkin. They thought they had the rebels by the balls and they never expected that the rebels would be crazy enough to attack with small fighters instead of with frigates and other capital ships.
Then, when the attack happened with small fighters, Luke managed to score a one in a million hit by squeezing his torpedo right into the vent (the hard part) and the torpedo then auto-locked onto the greatest energy source and flew/guided itself right through the ventilation system (the easier part).
I'm not seeing any gaping plot hole there. If we want to talk plot holes then I'm wondering more about…
- What happened to the DS tractor beam system? It managed to disable the Millennium Falcon's avionics systems from pretty far away… why not the rebel fighters or the MF when it swooped in at the last second?
- Why was the 1st DS not protected by at least a small fleet of S(S)Ds? Where the hell was the (huge) Imperial fleet? The DS had no escort at all? Seriously?
- Why was there only such a very small number of TIEs? The DS should have easily been able to launch dozens upon dozens of squadrons…
I'd consider the proton torpedo thing a rather small and actually "fixable" (with a bit of filling in the gap thinking) issue in comparison.
. Is that what you mean? The exhaust vent "hole" = the plot hole?
