Avimimus

I initially read 'tomatoes' as 'tornados'...

For spawns that move - how would that be a problem? They'd just initially spawn over an area that is twice as wide (i.e. every second block), and that is only if they are on a slope). I could see needing to make half-height variations for every plant (which would be a chore, but doable), but all of the animals shouldn't be an issue because they don't stay in the same place anyway. P.S. Thanks for the tip about the step-up mod. It doesn't fix the really cliff-like terrains (which you can't climb because they are too steep), but it is definitely less tiring.

Very interesting. There is a lot I hadn't considered. That said, usually the outer layer of any material (whether it be sand, gravel, or soil) is pretty contaminated by rain, roots, and oxidisation. This is even true of some types of rocks, where the outermost layer will have oxidised. So with the exception of some rocks, having the first half block produce nothing of use for the player might be pretty immersive. The issue with vegetation might be more difficult (requiring producing plant variants for half-height bricks)? A nuisance but doable? Beyond that I don't see any other issues (assuming the half-blocks are just there for aesthetics and locomotion). I'm curious if you know of more (beyond those you've raised)? I'm quite curious.

This may seem like anathema - but has anyone considered a worldgen option where the terrain/elevation changes are half-height blocks? It'd make it much easier to navigate rough terrain, and it would look more realistic. I know it violates the minecraft-like aesthetic, but I think it would also make them game more distinctive, and it could have a lot of practical benefits. What do you think? Yes or no?