So we will see Fiji take no hit to performance when Enhanced Godrays is turned on as it has the tesselation improvements of Tonga. Moreover Fiji is a bandwidth and fill rate monster so expect some amazing results at 4K and even 1440p at times.
You can't take such a conclusion out of what you posted. If the architecture diagram is right, then we have Tongas Front end in Fiji, but with massively more Shader Power. If the Front end would be doubled like everything else, then you would be right, but unfortunately it seems not. We don't know whether other improvements were made. This is for me the only question mark, which might limit Fury a bit. Shader are up 45%, Bandwight ist good and Rops also won't limit. But Front end didn't scale from Tonga, so will be interesting whether it might be a limit.