So, some second thoughts on this.
I was able to get the virtual heightfield mesh (VHM) working, and somewhat well by my standards. All I-myself really wanted out of tessellation was to add that fine-level of detail to help break up the mesh, etc, it’s all texture/material driven which is handy, all the reasons we like.
For landscapes SPECIFICALLY, it was always such a hog, costing me 10’s of FPS (that ■■■■ RenderQuery!!!), BUT whereas the VHM always crashed for me, I managed to get it working today.
ref: Finally getting the hang of the newer heightmesh in UE426! - Album on Imgur
Results look GOOD to my eye, pretty much what I wanted to get out of it, so for landscapes at least, I am VERY happy with the VHM as a replacement.
That leaves static meshes which seems to be nanite as a solution, but I’d still like some kind insert-extra-vertices-here type of thing. For me, it’s the idea that I can tie it to material logic that really makes it happen; just smoothing-out’ a surface by inserting vertices is good, but I’d still want that low-level control over things so it comes out exactly as I see fit…