I'd say it's the modularity and not just for storage purposes but for variation and depth. Especially in games where you can destroy the enviroment like in 40k 2nd ed it makes the game amazing when you can just melt rocks and poison forests to deny cover for enemy and make way for charges. When you reach point where you got multiple boxes of terrain to use its important that they can be used together, so having a single fughueg terrain will always be that same piece no matter how you place it on table.

Same goes for interactivity and accessability, you need to be able to move your models inside the terrain piece like multistory ruined building. I don't like fidgety stuff like actual doors that can be opened, simple removeable door or hatch is superior. Models shouldn't fall off from heights or tip over on hills so that's also something to consider.

They also should be durable enough to be handled and cheap enough to not be a major financial loss if its broken. Oh yeah, and preferably as non-toxic as possible, no need to cause yourself any more damage.

Even if I don't make dioramas, the terrain making is a hobby of its own and should be considered as such when making it. You need tools and materials for it and should always be on lookout for such things, like broken toys and scraps from construction yard.

>>96158234
>>96159419
These anons have right idea