There was another solution proposed in the past, to give more height map points per tile, but:
- it won't allow to create some effects ("cave" like or hangover for example - only slight ones, to don't get issues with units movements);
- it will waste memory for most of terrain (mostly "flat" parts);
So I'm proposing adding new feature like objects (not destroyable and not passable) for each tile set, roughly corresponding in shape to current cliff tiles (including transitions ones), with exception that we should have more than one for each existing corresponding tile (to get more variety).
That would be for new maps only probably (unless there will be nice algorithm to translate existing ones) and require slight redoing to take advantage of them.
It could be used to mark not passable cliffs in cleaner way (for example have boolean property deciding if it should or not to be - I think that we might have that already).
Also that could be used to get rid off flat craters (not destroyable but passable), even if (as Berg pointed) it would lead to slight wheels sinking - that is better than flat craters anyway.
The main issue I find is that it might be hard to nicely, seamless blend them with flat terrain.




