It was upgraded and optimized to work with D2R Items Diablo 2: Resurrected but remains rooted in 20 years-old technology, and is having a trouble keeping up with "modern game play."

"In 2001, there wasn't nearly as much content available on the web about how to play Diablo 2 'correctly' (Baal is played for XP as well as Pindleskin/Ancient Swers/etc to magical finds, etc.)," 

PezRadar said. "Today but, a novice player can search for numerous amazing content creators who can instruct them ways to use the game various ways.

Many of them entail a lot of database load in the form of creating loading, degrading, and then destroying games all in a short time. 

Though we did foresee this--with players creating fresh characters on their servers that are fresh, striving to find their items to be magical, we largely underestimated the amount we could have gained from beta testing."

Another issue is the frequentity of database saves across the world, which happen far often without a good reason. 

Blizzard has implemented some changes to ease things up at present and is working on a more permanent solution, but it's sometime in the future because it's "an structure overhaul that will require time to Diablo 2 Resurrected buy items develop the system, test it, and finally implement."