It is already problematic. DRM may not be "always online", but from what others noticed, it needs to connect from time to time, in order to validate and allow access. Which means, no fully 100% offline Single Player. DRM for me, is a partycrusher and a moodkiller, so i wouldn't endure it even if they paid me to (i always run Diablo 2 with NoCD, whenever not playing a modern version). Besides, the new graphics seem to be cartoonish and WOW-ish much, colorful, with less gory/dark feel. Both DRM and new artwork, had been what made me stay the hell away from Diablo 3 in the first place anyway; so, i think i ain't touching the Diablo 2 "demaster", either!
On the pros side, Blizzard said there is going to be mod compatibility, the stash is expanded somewhat (although nothing great like Plugy) and there is a small number of mostly useless, quality of life improvements, such as cash being auto-picked up. Sorry, but i simply cannot find it to my heart, paying 40 bucks for a game that i already own twice. The things it adds is your typical modder's free tweaks and whatnot.