A vision of Randomized Hostile Structures with procedural generation

The first time you explore a temple is the only time its interesting.
Once you know how to safely get the loot of a desert or jungle temple; that’s it.
That’s all they are. All subsequent temples can be dealt with the same way. Eventually, there is no thinking involved as you automatically dig your way to the treasure.

The solution is randomization. Just take a peek at roguelikes and the answer is clear.

Even a small selection of, lets say 8 random traps/obstacles, 6 puzzle variations and 2 different treasure rooms could give the players something new to learn and would decrease the downright sad repetiveness of those ancient structures. Randomize the solution for those puzzles, too.

Why stop there? The Dungeon (Monster Room) is just a cube, created long ago. It's outdated.
And it's the same problem, really. And the same solution, too - practically yelling in my face.

Make it larger (not too large, maybe 5-10 rooms). Multiple spawners and different rooms would make the Dungeon a challenging and interesting place to explore.

Finally, different temples and dungeons can focus on different themes. They may also teach the players about the game’s mechanics, spark theories by telling a story through their purpose and design and just bring more exploration to Minecraft.