So many things wrong, where to beging...
1) I said W/M, a combo already wearing a shield in PvP. It also seems that you have no idea how strong SoD is...
2) M/W can't even equip a shield. And if it could, you can make a macro to equip low level white shield, pop SoD then go back to your main weapon...
3) 4.5k dias is not even that much. Around 350m gold in Mithras. Specially since you can just buy it over time.
4) Lv50 CC would still be a lot of free damage.
Anyways. In simpler terms you might be able to understand that doesn't involve game mechanics. Your suggestion does nothing to solve this issue:
I'm talking about allowing people to create unique toons that aren't cookie-cutter guys.
There will be that optimal skill per class and mostly everyone's going to pick it. It'll be the same thing now cookie-cutting that's going on now.