Some strength coaches see a good deadlift as the outcome of excellence at other disciplines, so there is no need to specifically add deadlifting itself to a solid program.
Personally I could take or leave DL, I have it in my routine right now but I sumo lift as I need to work on hamstring strength due to suffering from backpain largely due to pelvis alignment issues. The other thing to note about sumo is your lift succeeds or fails in the first inches off the ground where the power is going through your legs and your back is fixed in a "strong" position, whereas your classic deadlift stance the off the ground is the easy part and you are fighting with the weight getting upright where your back is at its most vulnerable.