In recent data analysis, the difficulty settings of reaper of souls had some changes. Monster power is adjusted from level 10 to 5 which is similar to console version. Nightmare in game difficulty settings has been removed, while another one named Torment instead and some related achievements.
A player put forward a proposal – reduce a difficulty setting. Like the picture above said. Many players think Diablo II is better than Diablo III. They think diablo3 has lost many interesting things in diablo2, like ladder, and difficulty setting in this discussion. This suggester insists that 3 difficulty settings are much better than 4.
Community manager explained this doubt as before. Difficulty setting in reaper of souls will have more control for players in the future. The development team has the plan and are working for it. The goal is on the way but more details are not available at the moment as usual.