I was actually thinking about the same as well. The 970 only has a 145W TDP so my AX760 would easily handle couple of them, even with CPU overclocking.
But I would rather have a strong single GPU still. Like I've stated previously I'm not a fan of multi GPU setups.
Well yea, preference for a single card is one of the very few reasons I can really think of for paying that extra money for a 980.
Either that or people could wait and see how the prices fluctuate in the next few months before TW3. If the 780Ti drops like $50 below a 980, then it's probably worth grabbing the 780Ti instead... Although it also depends on how all these new technologies like VXGI & MFAA pan out. If they are Maxwell exclusive and end up being incredible, then it might be worth paying the premium for a Maxwell card. Always lots of variables this early at release.
On the SLI front though, as someone who has used SLI 680's for almost 2 years now, the only game I had big issues with was Wolfenstein: TNO (because they literally didn't have SLI support), I think SLI is great. Witcher 2 at Max with Ubersampling went from ~40FPS to ~70FPS from a Single 680 to SLI. If the 9xx Cards can see that kind of result, especially with The Witcher 3, then SLI will be the way to go.