How do you know?
Seriously, how?
You can "just tell"? I guarantee you, if that's your yardstick, you're wrong almost half the time, at least. (Not just "you" personally, but "you" anyone.) Seriously. Unless you know the people writing the books, you have no way of telling. I guarantee you, some of the ones you think are the most obvious are actually not nearly so clear-cut.
Especially considering the fact that there really isn't a solid line of demarcation between "flavor" and "mechanics" in terms of which came first. Usually when an idea comes to an RPG writer, it has a mix of both from the get-go.
Well, to be fair, there's no way to KNOW exactly. However, you can certainly get a good sense from some rules that are difficult to comprehend from a game point of view but make perfect sense by a simulation point of view.
I mean, I'm certain no one sat down and thought "You know what would be fun, we could make Longsword the best weapon in the game CLEARLY." when they were writing second edition. And I'm certain no one thought very much about how fun it would be for the game when they printed 20 weapons with the exact same stats with different names. Instead, they were thinking "We need the stats for a Falchion, they should be about the same power as....this weapon here." I find it extremely unlikely that back in 1st or 2nd Edition the writers were actually thinking to themselves: "We need a weapon that does 1d10 damage, is two handed, and is piercing so we can make sure that there is one of those in the table to round it out. Now, what do we call it?"
It's certainly possible I'm wrong. But I wouldn't have thought like that back when I played 2nd Edition. The entire concept is that the game is supposed to simulate the real life properties of the items. You start by looking at the items properties in real life and them attempt to model them in game mechanics. You trust that whatever kept them balanced in real life keeps them balanced within the game world. And even if they aren't balanced, who cares? It just means that no one will be running around attempting to take out people in plate mail with a dagger. Which only enhances the simulation.
On the other hand, I've changed my way of thinking over the years since I've played more and more gamist games and realized that they are simply more fun for me.
As for the original topic. Not everything about 4th Edition reminds me of 1st edition. But there is a slight shift back to letting the DM make stuff up that doesn't follow the rules precisely if it is fun. There is a shift back to putting the focus more on the roleplaying at the table and less on the skills on the character sheet.
For instance, in 1e it was perfectly acceptable(and expected) to find a well that when you drank from it gave you a permanent bonus to a stat. I probably wouldn't use this one in 4e for balance reasons, but it seems perfectly acceptable by the rules to say "Someone created a ritual to make water that permanently increased the strength of the drinker."
Whereas in 3e, if I found one of those, my thought would be "Wow, that seems like someone would have had to imbue the water with a wish spell that continually refreshes itself. If that's the case, I should be able to drink 5 times in a row and get my strength up by 5 points. It also cost him millions of gold by the magic item creation rules. Which seems odd that they'd just leave it here...being worth more than a couple of kingdoms."
So, it likely wouldn't be done in 3e, because it seems like it is contrary to the spirit of the game rules.