So, the concept of fungibility is also something that's useful in looking at adventure design, though once again it's a useful tool, not an automatic indicator of quality or a lack of quality.
First and foremost, it's an important element when looking at the objective of an adventure. A lot of times the easy hook is a giant sack of cash (in some form or another) , but that can end up raising questions. If the goal is money, is this really the best way to get it? A lot of classic games raised this question, where the rewards of an adventure could easily be overwhelmed by the cost of potions, repairing equipment and so on. If you've got a fungible reward, it invites that sort of comparison thinking, and that's a good way to end up with heros who act more like accountants. Taking a little time to make sure the MacGuffin is non fungible is probably a good investment of time.
That's a small thing, but it does provide a pointer to a bigger one - Heroism is Fungible.
Not the concept of heroism, of course, just heroism as it exists in games. Menace rises, heroes arrive, fighting ensues, heroes win. The problem is that in many cases it does not matter which heroes arrive to save the day, and this is especially problematic in hero-rich environments (like the many published RPG settings). This is a common problem with published adventures because they need to work with whatever group happens to have bought them. By working equally well with all groups, it's unlikely to have any kind of personal tie in to your particular group.
It's hardly news that published adventures are a little generic, but it's useful to frame it in these terms because it gives a concrete yardstick for any changes you make to personalize it. Does the change you're introducing make the adventure one which only your group could handle it or does it just make it more complicated?