Powerful geometry engines are never a bad thing but aren't most of today's AAA games more compute limited than geometry limited ? I suppose this explains why Maxwell fares better.
We can project Pascal to be even more compute focused.
For those wondering I don't think our little discussion is off topic, far from it as it is directly related to Rise of the Tomb Raider which uses compute for many things.
This has the profile of a game favoring AMD, I'm not going to be shocked if it performs noticeably better on "corresponding" AMD hardware (7970 vs 680, 290 vs 780, 390 vs 970, 390X vs 980 etc..).
I believe the amount of compute-shader usage is fairly small in many games for the whole rendering-time.
Only now we have this more heavily transition towards compute, since we left the last generation consoles.
In contrast to simple compute-shaders, where "simply" the shader-array is important and GCN is very strong we have pixel- and vertex-shader stuff and sometimes even geometry-shaders.
Here are many different things important, the Rasterizer, the ROPs and how the architecture eats the different Data-Input.
Many stages where Nvidia is quite good at.
The first TressFX Version for examples uses compute for the hair simulation, but it also needs to render those hair and uses geometry-shaders for some steps, where GCN really sucks at, because of the wide thread-group-size of 64 vs. 32 from Nvidia.
The parallelism of geometry-shaders is really small as I understood, so you loose more performance the wider the machine is.
One reason why you don't really see that GCN is much better than Kepler.
TressFX 2.0 changed the execution model a bit, now it uses vertex-shader where previously geometry-shaders were used.
Now in theory AMD should scale better.
On a side-note, HairWorks uses Geometry-Shaders and Tessellation, it uses all Shader-Stages available on DX11.
Not quite the best technical solution, for any architecture.
For Tomb Raider we have adaptive Tessellation for the snow, I'm curious to see how well Nvidia and AMD performs at it.