Still IMO a valid goal to work toward in one's world/universe building, no?
For
universe-building, sure.
But I'm not talking about
universe-building. I'm talking about the process of actually
playing.
The cynic in me thinks the locks are all designed to be pickable in the same way in order to make life convenient for those who need to, in a non-criminal way, do the picking.
Well...I mean, no, not really. It's just that a mechanical device which fits into the kind of space it needs to (a roughly inch-/2.5cm-wide cylinder no more than a couple inches/10cm deep, or a block no more than about the size of a playing card deck, perhaps stretched or squished a bit) doesn't really have a lot of
options for how it can be designed in order to still be usable. The vast majority of locks IRL use pins (or wafers, for low-security, high-wear applications) and springs. ("Dimple" locks are basically just sideways, narrow pin-tumbler locks, and vulnerable to most of the same exploits.) The only major exceptions are "disc detainer" locks and tubular locks (e.g. the kind used on vending machines, with a key that has a cylindrical shape), which require a specialized tool for easy picking and are relatively modern inventions. The best high-security locks (e.g. those used by the US military to lock nuclear materials!) are, functionally, just really really high-quality pin-tumbler locks with extra pins, and picking them is, again, mostly a matter of having the right tool to make it easier. Old-style "warded locks" are basically never used anymore except for cosmetic purposes, because they're almost trivial to pick and extremely susceptible to skeleton keys.
It's not really a matter of anyone conspiring against anyone else. It's that a machine that is simple to use, small enough for purpose, resistant to wear-and-tear/dirt-and-grime, and which works
consistently with the right key, has extremely tight design constraints. Or, to turn an old phrase, if you can build a better locking mechanism, the world will beat a path to your door...and then be unable to get in because it's locked.
And this comes down to a question of accuracy vs entertainment. It's the same argument I hear when I use pop-culture Xena-like versions of the Greek deities instead of the historically-accurate versions; some say I should use the historically-accurate versions out of a sense of realism, where I prefer the pop-culture versions for the sheer entertainment value.
But are you actually willing to use that argument? Are you willing to commit to it?
Because that opens you up to a number of rebuttals I'm not sure you want to face. Like the idea that, because it's a game, it should be designed to be entertaining
as a game, in addition to and separately from its realism, historicity, etc.