Then I am going to hope for a 1+2+expansions remake in the style of console 3 for Switch/Ps4/PC
I just do not understand how these posts keep happening. Blizzard doesn't do Blizzcons unless they have something to show, it's why they canceled the one a couple years back. We know Diablo is going to be the center of attention because of these merch leaks, that the Diablo panel is immediately after opening ceremony, etc etc.
Judging by their job postings, they are making a mobile game that's a mix of a co-op RPG and a board game, so if we imagine something like Gloomhaven-esque Diablo game, that would fit very well.
I think it'll be both. They'll announce a new Diablo is in the making, but they'll also release a remake of D2 inbetween because they've been remaking their old games and it makes a lot of sense to remake D2 to prepare for the release of a new Diablo. Acts as promotional material and should be relatively low effort depending on what they do(widescreen support which can already be modded, some QoL changes like gold pickup on walking which is already modded etc).