I know I'm being outspoken minority here (and I have virtually NO experience with this...)
Looks to me like the DD wasn't at fault - I mean, the spacer looks pristine. So IT didn't fail. The failure looks like the skid plate, and those drop downs didn't help the matter.
Why do I say that? I'm guessing that the drop-down caught the rock, right? But the skid plate still bent, and that was what actually caused the damage. I don't know what brand skid plates you're running, but I'd talk to them and say something like "Dude, your metal didn't hold and really jacked up my truck. WTF?"
Are DD's bad in the first place? I don't think that should even be the point of this thread - but again, I defer to those with more knowledge. Better road armor should be the real point, or at least FAILURE of the skid plate. (someone else pointed out that there are skid plates that should fit over the DD)
The skidplates were modified to clear those spacers. Had the spacers not been there, the bottom would have been smooth and I would have slid right over the obstacle without suffering any damage.
As for going with other skidplates, All Pro and ATO do not protect the lower control arm mounts.