Make use of physics.
dry wood can burn,
water can extinguish,
fabrics can tear,
grids can be cut,
oil can make surfaces slippery,
thin walls can be broken,
ropes can snap,
ropes can be knotted,
steelbeams can melt,
metal can become weak under the influence of heat,
friction can generate heat,
loops can be knotted,
knifes, scissors, swords and other pointy things can actually stab and penetrate softer materials,
ice can melt or be smashed,
and all this not just where it's needed.
Don't take the player by the hand so much.
Allow the player to make mistakes.
Reward the curiosity of the player.
For the example of the locks, make them as large, varied, and unobtrusive as in real life, and more importantly, make them consistent. If you can unlock or pick one lock, you should be able to unlock or pick all locks, even at the risk of running into a dead end or not being rewarded with highloot behind it.
I know that doesn't make the level and game design any easier, but that's not the point. It's about progress and gameplay-wise we've been stagnating for 15 years.