A recent developer blog details how Greater Rifts are designed within the game. Greater Rifts provides players with the maximum amount of challenge found in changing circumstances, difficult monsters and providing opportunities to overcome along with balance and diverse styles of gameplay are factored in.
Variety keeps Greater Rifts fresh and compelling over time. Each one is intended to be a little bit different, even if it’s something small like giving your character stalagmites to break for an extra speed boost.
Just as each rift is different, each class has unique strengths and weaknesses in dealing with the challenges rifts provide. Some floor layouts or monster types will be more challenging for specific classes, but the diverse nature of rifts ensures the next floor or rift can be one where your class excels.
You can read the full blog post by visiting here.