Up until the catastrophe that is Warcraft 3: Reforged, I was all for a Diablo II remaster. Not any more.

With Warcraft 3: Reforged, Blizzard committed the ultimate sin: It betrayed its legacy fans. The original Warcraft 3: The Frozen Throne doesn't exist any more. It's now lost to time. The only Warcraft 3 that exists now is Reforged, and all older versions must now be updated and replaced with the remaster. You can't play custom games the same way, the UI has changed, and ultimately the core old-school experience has been carved out. You can still play with the original graphics, but the game is on the new wonky Battle.net 2.0 framework that doesn't let you do basic stuff like browser chat or even check your profile stats.
I can't imagine a worse fate for a beloved yesteryear game. This method is basically a means of bringing an old classic forward by smashing a square through a circle-shaped hole. If Warcraft 3: Reforged is how Blizzard plans to remaster its fan-favorite games, then I really hope they just stop here. I hope they don't touch Diablo II.
This kind of thing would annihilate Diablo II's core multiplayer focus. The smallest of changes will have a radical impact on these older games because they were built for another age. A shift in UI, for example, can cause big problems with you're battling demons or taking on hordes of enemies.


Diablo III's main game UI/chat interface (left) compared to Diablo II's more robust social features (right).
The biggest issue with a Diablo II remaster would be forcing Battle.net 2.0 hooks into the game. Diablo II: Lord of Destruction's online realm play thrives on three basic things: Chat lobbies where players can come together and put up trade offers, team up, and theorycraft within the game (this was before Discord); Private games that allows users secure worlds to trade, do runs, or duel; and the ability to make games on-the-fly, which served as real-time listings for specific activities like Baal runs, trading, Cow levels, you name it.
Without these things, Diablo II's main multiplayer focus will falter. This social system is put in place for a reason, and if anything it needs added to or refined, not cut apart. Battle.net 2.0, for instance, doesn't let you actually make named games, and the chat interface is extremely barebones. There is no free chat lobby with interactive channels, or a lobby that lets you inspect other players in a freeform environment.
The worst possible thing Blizzard could do, though, is erase the original Diablo II and Diablo II: Lord of Destruction games and force us to download the new remastered version. This goes double if Blizzard were to wipe any mod support or even cause conflicts with popular mods like Plugy.
This could wipe out years' worth of work from singleplayer users who have been diligently grinding away at their Grail lists (these players try to find every item in the game) who use Plugy to expand their stashes beyond reasonable limits. Right now Diablo II is a very niche game but has a strong following even still, and there's an allure with hardcore fans. Even as Realm servers are all but dead, gamers are jumping into singleplayer to tailor-make their own experience and grind, grind, grind.
It's same type of nostalgic allure that led users to buy Warcraft 3 Reforged in the first place. Everyone wanted to re-visit the campaigns, those old crazy custom maps, and the general social-driven camaraderie and chaos the old-school RTS had to offer. And it's the same type of desire that Blizzard betrayed with its weird legacy-breaking remaster.
So Blizzard, I implore you, please just leave Diablo II and Diablo II: LoD alone. Focus on Diablo IV and Diablo Immortal, and close the door on remasters once and for all.