I have strong confidence that Blizzard won't mess up Diablo II: Remastered, and my worries have been allayed.
When I first heard Blizzard plans to remaster classic games like Diablo II and StarCraft, I was very concerned. As a long-time D2 player, Blizzard's recent moves with Diablo III completely alienated me from the franchise. Gone were the best features that made Diablo II such a great game: chat screens, trading, 8-player co-op, and game room lobbies, all of which were facilitated via the original Battle.net framework. Of course, Diablo III uses the new revamped "Bnet 2.0" which gimps a lot of the features found in the classic service. I thought for sure Blizzard would completely change core Diablo II features if it ever remastered the game, simply because that's what it did with Diablo III.
But Blizzard has proven they understand how to remaster their old games without ruining them. StarCraft: Remastered uses the same Battle.net client as its original, and has cross-play with the classic PC RTS. The only thing Blizzard really changed was the graphics; everything else was left intact: lobbies, chat system, game rooms, it's all there. This gives me strong hope that Blizzard could do the same thing to Diablo II and revitalize one of the most compelling and enjoyable PC gaming experiences of my time.