I've read a few of their patents awhile back, AFAIK, this isn't a tile based rasterizer, but simply a more efficient rasterizer in general.
Though contrary to the myth that AMD's rasterizer is what's holding them back, it's actually not true. ROP bottleneck will show a distinct behaviour in games, as resolution rises, the relative performance will drop. Anyone who has paid attention with GCN knows that as resolution goes up, it's relative performance is actually stronger.
AMD's biggest problem with GCN is the inability of most game engines fully utilizing it's shaders. We've seen what can happen with good programmers with Doom Vulkan, using Shader Intrinsics and Async Compute to max out GCN, RX 480 ~20% faster than 1060, which actually matches it's paper TFlops specs. In most games for GCN, there's a lot of SIMDs with idling ALUs doing nothing so in effect, it's not a 5.8 TFlop GPU since that rating is the max theoretical perf assuming all ALUs are working.
Going with NCU's variable width SIMD layout will solve this issue, so we should get a more closer and truer comparison of paper spec TFlops to gaming performance. ie. A Vega of 12.5 TFlops will absolutely wreck Fury X.
Btw, per the patents, it's not all variable width SIMDs. Each CU has 1x 16 wide SIMD, and 3 to 5 (depending on the configuration) of variable width SIMDs (12,8,6,4) along with twice the Scalar ALUs (that are extremely fast at processing some shader instructions, think of it as a "bypass traffic, go super speed") of current GCN per CU.
All of this sounds great, the obvious question would be, why didn't AMD go with this design from the start? Why the 4x 16 width SIMD layout that they would have known would have issues with under-utilization? It's all down to the feedback mechanisms and a really dynamic hardware scheduler required, to be able to combine multiple variable SIMDs to process instructions that require 16-ALU SIMDs. AMD just didn't have this tech back then as we see their patents, the bulk of it addresses this new HWS technology to enable this kind of design.