So what is the consensus on using all emmissive armor versus using 1 or 2 and the rest regular? Were designs of the latter due to the armor bug that was solved? Is there any reason not to use all emmissive (other than cost)?
Emissive armor doesn't really stack, but it will apply it's effect whenever an armor panel is damaged. So, if the damage is split between two emissive panels, you'll get two damage reductions. So most players will use a high percentage of emissive armor.