Making 'stairs' more than just a weird stone ladder.

The function of stairs is to enter, leave or just to change one's level in the space. You will need to answer these four questions:

Shape O' Stairs

1. Stairs: straight up &/or down, single or dual,
2. Shaft: ladder, elevator-dumbwaiter (cage/room), disk, open
3. Switchback: straight or curved / 1-4 switchbacks
4. Curved: Spiral, double helix, curved (single or dual).

Where Guards & Doing What?

1. Guards In & Around Stairs: at top looking down, march-pacing, sitting on steps, standing at entrance point, hiding in shadows
2. Defensive Guards: behind door with sliding eye-peep, crossbow slits, massive shield(ing), booth, alcoves, on stands, other side of portcullis, behind rows of pointing spears, ready to trigger an offensive trap, on ledge-loft-platform,
3. Observing nearby: before, after, above &/or below actual staircase.
4. Offguard-Guards: asleep, preoccupied (gambling? play fighting? eating?), missing (on break?), dead/wounded &/or change o' the guard.

Guardians: 'Who Goes There?'

1. Guarded with traps: noise, hurt, capture &/or stall intruder-invader
2. Guarded with sentient beings
3. Guarded with beasts, monsters &/or guard animals
4. combination of two &/or three of these

Stair Go Where?

1. access to way out: entrance &/or exit
2. access between 1-4 other levels &/or loft-ledge areas
3. false entrance / real entrance nearby or connected to this one via trap-secret door
4. multi-use stair: also used as a library (books in walls), bedroom, staging area OR transport of foodstuffs &/or trade goods.

Special Cases / Stair Cases:

1. Shifting, Moving &/or Dancing Staircases: think Harry Potter's Hogwarts with straight-switchback staircases that rotate to face different directions - or Dumbledore's corkscrew spiral staircase, 'shelf' parts as sliding individual stairs pop out of walls, floating-moving rocks
2. Trap stairs: turn to glue, break off, go 'flat' (one long slide), all collapses all at once, large object(s) roll down from the top, explosive runes, slippery (especially near top), handrail knocks top person off balance then breaks,
3. Monster Stairs: one or more stairs is a mimic, carpeted stairs are partially a trapper (it can roll once it captures person(s) / sharing impact damage), statues in frescos-alcoves are gargoyles, golems, animated armour, hanging mobile-sculpture made of animated swords, pull-grapple nasty hides behind illusionary wall / grabs last person
4. Fancy stairs (&/or wall-railing): sculpted, rune-embedded, light up, open face, alternating or single-foot stairs, each stair is a 'swing' held up by four cables, each face has part of a larger painting, each surface or face has writing / part of a message, each step some specific shape (a wing, a stone person-sculpture, teeth ('careful, they may bite'),
5. Nifty thing in middle (spiral staircase): fountain, chandelier, climbing-hanging plant(s), statue(s) compilation w/ parts (may show-tell story as you climb), spinning-light animation stop-motion tube (show on walls of stairway), floating objects, mobile-sculpture.
6. Odd Material (stairs &/or walls &/or railings): Glass-marble-quartz, wood (solid, veneer, laminated) , each step consists of hundreds of spikes ('great traction!'), glass-top / covered 'drawers' displaying items on each step, liquid-fountains / pressure-float, moving hands that grip your feet / help you climb (or any mass of one specific body part), bone, ivory, leather, wind, invisible / mystery (any material), sound, wires, macramé strings, webbing, intertwined branch-root, sands (flowing or not), rolling marbles that somehow still hold you up, millions of insects (flying or crawling),
7. Overall Structure Odd: all parts suspended on string-cable-chain, floating objects (in water, lava, levitation, elongated 'spine', gravity shifting, mobius, Penrose, Escherian,
8. Each-Some-Specific Step(s): sound-note, step says phrase, step gives light, makes riddle, vibrates, taps out beat (only you feel it / no sound),
9. Illusion: any form or style (above) can be image &/or sound from illusion. Illusions are: cover for secret place-items, cover for lurking trap-monster, show-story, light-show, illumination, code, map, knowledge,
10. The Staircase Is All There Is: wizard's tower... is really just a staircase w/ landing-loft-levels, stairway to heaven/hell, each stair represents a different year of your life, each stair edges on a teleportation portal to the side, jack's beanstalk, Dr. Who's Tartarus-Staircase, Mordenkainen's Mansion... As Stairs

The basic dungeon does well with a simple roll of the d4 - up to four rolls. If you want more, add some of the ideas from the Special Case Of Stair.