Kinda weird if you ask me.
The first key feature was the graphics.
https://diablo2.blizzard.com/en-us/#visualsThat also includes a frame-skip for the old version just to make the new version look smoother in the preview.
Next key feature is the cross-progression. If only there wasn't the "Cross-progression requires a linked Battle.net account and separate Diablo II: Resurrected purchase for each supporting platform." So if you indeed want to play Diablo2 on your pc, your tablet, your PS5, and most importantly your phone, you need to buy 4 copies.
The next key feature is basically an in-build plugy. But without unlimited stash. But no worries, I'm sure they'll add a DLC for more stash pages. At least that's what the interface already looks like.
So all in all there are 2 features that would justify buying it: the graphics and shared stash.
Are there any news about how breakpoints work in that game? That would ruin or make the game depending on the answer. For me at least.