This is exactly what happens in the movie already though. The flaw Galen left on the Death Star was a leaking reactor. How to get to the reactor is a whole different matter - Luke’s miracle.
I don’t disagree with that. This was just an idea I had to address this issue, which I have heard brought up from time to time. I’ve argued against it before, but I can see where it is coming from as well. Kind of want to get a sense of people’s feelings about it.
A lot of your ideas for Rogue One seem similar to mine, but this one in particular I don’t agree with. I think one of the better things about the film is that it retcons a frankly obvious design flaw to be an intentional decision rather than simple incompetence. I think making this change would diminish that, and the fact that Galen didn’t catch the flaw in the initial design would make him look boneheaded.
Use cuts and VFX to remove the data disc being handed off to the Tantive IV. Mask it out of hand. Maybe replace disc with blaster for the second rebel (since he has a blaster in his right hand when he makes it into the Tantive IV). We can assume both ships received the transmission.
I’m also not sure about this change. I think what makes the Vader hallway scene work is that the stakes are clear. The Rebels are desperately trying to hand off the plans while Vader is cutting them down one by one. If there’s no game of hot potato with the plans happening, the scene is just Vader killing dudes because it looks cool, and doesn’t have much of a purpose.
Personally, I think the way TM2YC handled Vader was more or less perfect, and I wouldn’t change it much at all.