If it's sufficiently sharp, and I mean corner to corner and across the entire focal length, I see it being a worthy replacement for a couple fast primes such as the 50mm & 85mm as well as serving as a 70-200mm equivalent on a DX body. I can see that being pretty appealing to someone who wants to get as much flexibility as possible out of as few lenses as possible or with as little lens swapping as possible. I'm not all THAT averse to lens swapping but I know some people are.
Reviewing the specs, I see she's gonna be a big girl; taking 82mm filters and weighing in at just over three-and-a-quarter pounds! Let that sink in for a moment... The Tamron 70-200 f/2.8 seems almost svelte in comparison, using 77mm filters and weighing in at just over two-and-half pounds. My Tamron 24-70 f/2.8 takes an 82mm filter but weighs a "feathery" pound-and-three-quarters.
Hmm...without OS/VR, that's a lot to hold steady by hand.
I concur. Considering the size/weight and lack of OS/VR, that's a big deal.
Then again, think about how much it would be with OS/VR.....