On the released screenshots it looks like AoMR will use the same type of cliffs as AoM which are basically just a terrain texture you can’t walk on.
It looks like they added some more rock props to it but that might just be beatifications that are added for the campaigns only.
AoE3(DE) has really nice looking steep cliffs. They are going up at a 90° angle which makes them look a lot more majestic then just a slope with a texture on it.
I personally like the rocks I saw in the screenshots but I understand the concern. I also would like to see bigger cliffs/more “drastic” terrain. But I still think other things have currently higher priority. (like hydra model for example 
)
yeah I saw the rocks too and they look fine but they are not everywhere so I assume they won’t be in random maps.
I like having the option to make AoE3DE like cliffs in the Editor when I make maps and they would likely look a lot better in random maps too.
My guess is that the rocks will be generated automatically when using the tool to create mountains. The density of rocks will probably be adjustable, like for the trees density for the forest tool.
Maybe but not as much I think, but I can only judge based on the few existing screenshots.
AoE3DE (and therefor likely AoM) has dynamic foliage and small stones and stuff on terrain. So it could be that some of the rocks are automatically generated too.
But a few screenshots have very big rocks on the cliffs, I assume those are manually places.
But in some scenes it looks like the bumpiness is just from normal maps, for example in the scene with Gaia and Kronos.