if you deadlift with proper form..and get low on the pull like you should..a traditional deadlift..sumo or conventional doesn't do as much to your back as you might think. I can see that thinking more along the lines of stiff leg'd deads or romanians...and even goodmornings are the same. But again...you can get hurt doing ANY heavy exercise..you just do your best to prepare yourself before you begin the movement. IF your'e CNS, muscle structure, etc. is used to it..it should have no problem... but if you go from only workin with 315 and 405 to trying 545 right after 405 yeah you're asking for trouble.
I added to my last post, take a look. I don't think the risks and stresses on those other exercises, which are multi-joint compound exercises, are the same. With DLs you've essentially got all the stress running through the vertabrae using only one fulcrum, only one point bearing the weight. DLs are barely a compound exercise; closer to an isolation movement, given that all the pressure & stress passing through a sole point of flexion on the lower back.
Add in the fact that i think the benefits aren't as great, factoring in substitutes for it.
On any exercise where heavier weights are possible i'd say stay away from low reps with heavy weights, which increases risk and isn't optimal for muscle development anyway.
Combine risk and benefit and you've got a different potential cost/benefit from DLs.
Some people just aren't susceptible to injury, and can handle good weight on any exercise wihtout getting injured. That doesn't mean that others won't get injured though.