The following bugs are extremely annoying, especially to composition makers:

Character passing through objects:

Infinite falling:

The Enhanced Movement mod fixes these bugs simply by spawning a helper object with only a roadway lod, and placing it above the Geom LOD (doing it every frame):

_ins = lineIntersectsSurfaces [
	player modelToWorldWorld [0, 0, 1], 
	player modelToWorldWorld [0, 0, -0.2], 
	player,
	_helper,
	true,
	1,
	"GEOM",
	"NONE"
];


(_ins select 0) params ["_pos", "_normal"];
_helper setPosASL _pos;
_helper setVectorUp _normal;

This can be done by the engine in a faster way with much less performance impact (e.g. probably no need to do a quadtree update like setPosASL does).

The helper object is only a small square surface in the Roadway LOD, which is extremely easy to make: