BSP dungeon generation feels structurally boring. Am I implementing it wrong or is that just the trade-off

Von Neumann is a solid call. Another option if you want to stay with Moore: just drop the survival threshold by 1. "Survive if >= 3 neighbors" instead of >= 4 keeps corners alive through more erosion passes without switching neighborhood types entirely. Less dramatic shaping but easier to tune. You can also mix passes, Moore on open room interiors and Von Neumann near corridor junctions, if you want finer control without committing to one rule globally.

The post-processing angle is probably the most practical fix here. What tends to work well is using BSP purely for spatial partitioning, which keeps the non-overlapping slot guarantees, then discarding the generated room shapes entirely and stamping hand-authored room templates into each slot from a pool. You preserve BSP's even distribution and connectivity properties, but the actual spaces feel authored rather than generated. Templates can vary in size within the slot bounds, which also breaks up the grid regularity. The main cost is building a template library large enough to feel varied, but once you have 20–30 rooms the combinations start compounding and it stops reading as repetitive.

The room pool approach is solid but the adjacency constraint logic is usually where implementations fall apart. Weighted random selection without accounting for what was just placed tends to cluster the same room types together. The weights don't update with placement context. Worth adding at minimum a recency penalty: down-weight any room tag that appeared in the last N placements. Even a basic “no two rooms with the same tag adjacent” rule makes the output feel dramatically more intentional, even when players can't articulate why.

Von Neumann neighborhood (4-connected, no diagonals) is way less aggressive on corners for exactly this reason. A corner tile has 2 live neighbors instead of 3 under Moore, so it survives more erosion passes before dying. I use Moore for cave/organic sections where I want irregular shapes, but switch to Von Neumann for a single edge-softening pass on BSP rooms, which keeps them recognizably rectangular while still breaking up that hard pixel-grid feel.

CA rule tuning in general is kind of a rabbit hole though ngl.

iteration count matters just as much as the threshold tbh. i've seen people copy someone else's CA settings and just run 10 iterations because that's what the example showed, and everything turns into smooth blobs. 3–4 iterations at a tighter threshold usually looks better than 8–10 at a softer one. less cumulative erosion, more of the actual geometry survives.

Two-phase CA gives you more control than either threshold alone. Run a tighter rule first, say 3 iterations at survive >= 4, to carve out the big open shapes, then drop to survive >= 3 for 2 more passes to clean up single-tile nubs and thin peninsulas. You get coarse geometry from phase 1 and fine cleanup from phase 2, without trying to find one magic threshold that does both jobs at once.

Another thing worth layering on top of the post-process step: a couple passes of cellular automata on the room interiors. BSP gives you clean rectangles, but a simple neighbor-count CA rule erodes corners and creates more organic shapes while keeping the overall spatial structure intact. You end up losing some rooms entirely in the process and that's fine. The BSP already did its partitioning job, the CA is just sculpting aesthetics. Running it on a per-room basis rather than the whole grid also keeps it from accidentally eating into corridor tiles.

CA on room interiors is great but watch out for aggressive corner erosion. Moore neighborhood rules chew through right-angle geometry because corners have low neighbor counts, so you end up with very organic cave shapes pretty fast. great if that's the aesthetic, less great if rooms still need to read as rooms.

quick fix: run the CA pass on a scratch copy, then restore tiles adjacent to doorway entry points from the original BSP layout. preserves enough rectangular structure to stay legible while still breaking up the pure grid feel.