I can’t tell why, but I never managed to be interested in Diablo 3. I bought it (with a discount fortunately) and painfully dragged myself half way through the middle of the campaign on normal. Tried several characters to see if it was the gameplay - still bored with all classes.
In the end I uninstalled and went back to WoW. Two or three years later, it was last July, I decided to stop WoW for good and bought D2R on a sale and this is still fun…