This seems pretty simple, really. If you're running a PVP-based server don't include DE.
I have DE in my pack. It's supposed to be OP. I have OP enemies to counter it. The pack is designed around what I already know about the mod.
If you're running a server that really wants to keep DE for the energy crystals, then that's ok, too. Disable the armor recipes.
The beauty of modded minecraft is that you can tailor your experience for whatever the goals are. Where balance is an issue, don't include the well-known unbalanced mod. Or, introduce harder enemies so it becomes a natural upgrade. Or, if your pack isn't really so much about surviving, then just don't worry about it because it doesn't matter.