NVIDIA has been doing well in directx 12 games that have been released. Gears of war was a disaster for AMD and in tomb raider the 970 was beating Fury. AMD does well on rumors and hype, not so much on reality
Facts... Brought to you by both NVIDIA and AMD during a joint talk at GDC:
Architecture specific paths are required for both NV and AMD. This was added to GoW UE with the latest patch and they're present in both Hitman and AotS.
Compute wise, GCN is far ahead of Maxwell as you can see here.
Devs are being told to always use Async Compute and maintain a non-Async Compute path for DX12 titles.
Framebuffer over commitment needs to be tackled by developer's. This is one of the big issues with Rise of the Tomb Raider
Once AMD work with the developers (Square Enix) of Rise of the Tomb Raider DX12, expect GCN to surpass Maxwell (just as it is the case for GoW UE, AotS and Hitman).
DX12, under Rise of the Tomb Raider, is a work in progress (the developer's have stated as such).
Factually speaking, your opinion is incorrect. Therefore based on what NVIDIA and AMD have stated, I am more inclined to side with the notion that if NVIDIA are to make head way, it won't be with Maxwell but rather Pascal and Volta.
GCNs superior compute shader, and multi-engine, capabilities, due to GCN flexibility brought on by being more CPU like (HSA), are also listed here:
Maxwell's short comings, in terms of Asynchronous Compute, slow context switching (up to 1,000 cycles delay) and preemption, were also listed by NVIDIA here:
Where as GCNs ACEs can pause, stop, start various tasks allowing for finer grained preemption. GCN can also execute a priority based compute shader in parallel with a current draw call (not limited by a draw call boundary for pre-emption). GCN also is capable of fast context switching as a result of the ACEs (1 cycle performance cost):