The word i used was subtle. Insted of having some in your face save of destroy that city with no ingame reason, there are some smaller choices that don't seem to have much consequences, but occasionnal bring subtle change in the world or in your own adventure.
Small choices with surprising and subtle changes to the world and your adventure, okay...for example?
The Megaton case is one of the worst offender of a choice that is supposed to be a game changing thing, but ultimately ammount to nothing. It has no consequence for the player or for the gameplay, and there is no given reasons about why it should be saved/destroyed. You do it for the evultz, just because you can.
I'm not sure where you get the impression that it was supposed to be game changing, but one option has Megaton destroyed, removing that entire settlement from your playthrough. Only one character survives, it affects other questlines, and though karma can always be changed it does instantly make you evil enough that the Regulators will start trying to kill you. I think it affects the traveling merchants too, but I only did it once and I never had a reason to check back repeatedly to see if they kept coming. One less place to find them makes a difference as well. Also Liam Neeson gets angry at you. As I already said you are given reasons to both save and destroy Megaton.
Burke
"You mean besides doing the world a favor by removing this pestilent scab of a town? Why, you'd be rewarded most handsomely! My employer is a very generous man. If it's bottle caps and luxury you're seeking. You shall have it!"
"Absolutely not! The place, the people, they're one and the same! Sacrifices for a nobler future. I assure you, they are worth ten times as much in death, as they are in life."
"I represent certain... interests. And those interests view this town, this "Megaton," as a blight on a burgeoning urban landscape."
"If this settlement were to... go away. Why, who would really care? Certainly not you, or I..."
"Megaton is obsolete. The last vestige of a cobbled, desperate past. It needs to... go away. And you are going to see that it does."
He also says stuff that might be more focused on ghouls, but at the very least informs us of his philosophy. I'm not saying it's the most brilliant writing in the world. You want to tell me it's shallow. Yeah, pretty much, but you're coming across as just plain unfamiliar with the game.