Not just in accessibility and automation, but features that are anywhere from extremely impractical to literally impossible to accurately implement at the table.
You know what's always bugged me?
In fantasy TTRPGs, lingering AOEs that have a clearly marked range and duration (and, thus, to a relevant extent, a volume and density), that say shit like 'spreads around corners', but provide no way of approximating their AOE in a limited available space - not even a bad method, just none - in DND5e, and even in Pathfinder 2e, they just straight-up treat all AOEs as ray-cast - like light: if it's in full shadow, it's unaffected, unless it spreads around corners, then only if you can draw a valid line to the target without leaving the AOE's radius.
Even a simple-but-wildly-inaccurate method would be great, something like "count all the squares of terrain that aren't occupiable (solid walls/etc), and redistribute them around the outer edge of the AOE, one at a time, clockwise, starting from a valid square on the edge of the AOE chosen by the player." It doesn't account for the fact that most things would expand evenly along the border, but even then, in many tight cases, it'd make a world of difference to the efficacy/danger of AOEs. No more easy-win placing AOEs at the far back of a room such that they don't cover half the space. But it's just not feasible to be doing those kinds of extra calculations every time an AOE drops, and heaven forefend it be moved. TTRPG combat is already enough of a fucking slog in most cases.
In a VTT? That shit could be automated and dynamic, on top of already having the pleasure of automated line of sight, cover, and visible area markers, among a thousand other amazing things. Dynamically recalculating an AOE's area as an expansion from cursor-point with a set volume to affect, after considering pre-set walls and other obstacles. Properly spreading it around corners and down halls and through open doors and such. I can't find one for Foundry, b/c it'd also be considered homebrew, and thus not most peoples' immediate focus, but it's a fascinating idea I'd love to tinker with.
When I eventually buy a Foundry license.
