Mineholes - You should leave the minehole in the CENTER and walk off of it, or at the least on the edges of what is it's minehole graphic. This will stop any 'blocking' mineholes, which IMO is bullshit last minute attempts at vaulting something or griefing.
Ladders - Placing an item on the bottom is ultimate trolling right now, you can jump into a place, toss something at bottom and people can't follow you.
Suggested fix: Character is displaced in that 7x7 if bottom of ladder is occupied.
Alternatively: The 7x7 area should be treated as an terobjs in so far as you cannot place other items where it is (besides rams / which should be the only object to be allowed there), it should act as a bounding box and never allow any item there.
House explosions and such things: Everything inside should fall neatly within the bounding box of the item, never tossed outside of it. (Throwing HFs over walls by breaking houses for example).
Houses - Should consider not allowing things to be at the top of the stairs.
Stairs(Mansion 2nd floor->1st) - Should either place you as close to the stairs as possible or in the MIDDLE of that first tile. I had left one tile between the stairs and the cupboard south of it, but the stairs move me on the edge of that second tile, and partially 'inside' the shiftplaced cupboard.