Is there any mathmatical theorycrafting to support your assertion? When I played WoW, people were able to make gear determinations by doing statistical analysis. I understand the desire to have best in slot in every part of your gear. However, sometimes that is more vanity then actual utility as well. I know people who would pay 1 million creditsd to change one mod that simply gave them 3 additional endurance (which is not statistically significant). Just for the sheer pride that it was best in slot.
I have been looking for, and and not yet found, tables that show how damage and mitigation scale and work.
Doesn't take math on this one.
2% damage reduction is priceless for the sin-tank since we are on the very low end of the tanks armor wise. 2% extra DR is pretty much what you'll gain going from rakata to campaign, maybe a bit more.
As far as the extra 5% shield on Dark Ward, it represent - lot of shield rating when you move forward in the harsh DR curve.
I personnaly spent 68 BH comms in the campaign armoring before the mods, so I got rid of the headgear and skirt. I realize its a bit of a setback for "getting geared ASAP" but i personnally don't mind it much, since I don't particularly care about beeing decked out in Dread Gear ASAP, I prefer my main to look as i liked.