^ You clearly have no idea as to why people were upset that 980 didn't have 8GB option. A hint: it had nothing to do that 4GB wasn't enough. It was about the fact that NV jacked up the price of their 960Ti (aka 980) from $249-299 to $549 and didn't even bother to throw in "free" VRAM on top of 970, to justify the insane rip-off premium for such a small difference in performance it offered vs. a 970/290X. This has been explained to you more than once. At no point in time was it suggested that 980's 4GB is insufficient. Therefore, you trying to correlate the desire for 8GB on an overpriced 980 vs. 4GB HBM on a Fury today is completely missing the entire context of the discussion last September when NV launched the 980.
Also, as has been repeatedly stated, but ignored by you once again, if 980Ti OC is very close in performance to Fury X OC, then getting 6GB of VRAM is a nice bonus. A lot of objective gamers on this forum are waiting for reviews of Fury X, and Fury Vanilla in July before even determining which is the better card to recommend/buy. Secondly, another point you miss time and time again -- this is a stop-gap generation. No matter what you buy now, by Q4 2016, newer cards will beat Fury and GM200 and by July 2017, we will likely see cards 50% faster, if not more. Therefore, your constant desire to keep pushing 4-5 year future proofing with flagship GPUs contradicts how most high-end PC gamers who buy $1300-1400 flagship cards in pairs actually upgrade. In order to reduce the overall cost of ownership, most Fury X CF and 980Ti SLI gamers will resell these cards in 2-3 years.
Without benchmarks and overclocking results, it's pointless to discuss 4GB vs. 6GB as deal breakers. And considering you used VRAM gimped 680 2GB SLI for > 3 years and have not upgraded to date, despite so many games using more than 2GB of VRAM, VRAM bottlenecks must not be an issue for you or if they were, you would have sold those cards a long time ago, as there have been plenty of opportunities to get nearly 70-80% more performance in 980 SLI as of Sept 2014. It sounds completely contradictory how someone could game for 3 years on 680 2GB SLI when even Skyrim with mods would neuter this setup, but yet now a hypothetical 4GB VRAM bottleneck sometime in the future is a deal breaker?!!!
By far the more important factors for a buyer looking at Fury X CF vs. 980Ti SLI will be how these cards perform in modern games/games they play, frame times in FCAT, and overclocking performance. These factors alone matter way more than 4GB vs. 6GB but we can't answer any of these questions yet. Finally, since you already stated you play games Day 1 on release, including a large majority of GW titles, it's already obvious 980Ti SLI is the solution for you. So go buy 2 Gigabyte G1 980Ti and enjoy them. It's really that simple -- not buying a $100k car or a $1 million house.