Simply unflatten the nether ceiling and provide late-game access

The nether roof is a desolate, featureless plain devoid of life, but still forms a unique location for players to enjoy, especially in the technical community. Only the most basic terrain details are needed to make it appear a polished part of the game. Gentle bedrock slopes from 1 to 3 blocks high would not change how easy it is to travel on, or steep, dense spikes of bedrock stretching from 3 to 6 blocks high can limit movement on foot.

Provide a late-game way to access the roof. One choice is for beacon beams to carve a hole ~7 blocks wide in the bedrock ceiling, allowing beams to reach the sky. Deactivating the beacon will remove the hole, preventing players from erasing large sections.

Mojang leaves clues to reveal game mechanics for new players so perhaps 10% of nether fortresses contain a tower where a staircase is cut off by bedrock, and a section is designed to fit a beacon base. Treasure can be encased in the bedrock itself.

Servers often ban the nether roof because easy long distance travel is seen as an exploit, so disable portals above the ceiling. Beacons need to be below the ceiling to create a hole, requiring travel there regularly first.

Lava ponds can provide stranded players an exit via death similar to jumping into the void in the End.

Ease of implementation is likely a barrier preventing Mojang from using more suggestions, so I hope these details are simple to develop while canonizing this unique and useful feature for more players to enjoy.