I know it sounds silly, but just think about it.
D1 had arguably the best story and atmosphere. All it really needs are more modern gameplay mechanics, a stash, auto gold pickup, some item and spell changes, and a complete graphical overhaul. The way they're handling the gameplay in the console version of D3 is pretty impressive so far, so I think they already have the right system in place.
90's RPGs are pretty popular these days. Just look at all those Final Fantasy remakes that handheld owners are gobbling up. D1 is also a fairly short game compared to D2 and D3, so something like the 3DS would be perfect for it. Throw in some online, and it's a done deal.
I know it'll never happen, but there's loads of untapped potential right there Blizz. You're welcome, BTW.