Yeah, from my experience and parse numbers the triple attack trait is actually worth the 12 set points. DoT is not significantly impacted, and the difference in WS numbers is very noticeable (especially with Epona's ring). As far as traits are concerned I believe the reason certain tiers are not currently allowed is due to balance issues considering buff spells we have access to or gear options we have access to. Accuracy is not a big issue other than on Heavy strike causing you to need a different set just to increase hit rate. Mab, we have Fantod, memento mori, and during right moon phase Plenilune.

I believe DWIII is probably not going to happen without the use of gear since it would open a very big DoT can of worms for blu when used in conjunction with other subjobs. Imagine a blu/war with DWIII, 9-10 shadow blink, double+triple attack, able to stack defender+cocoon, or the ability to further increase acc and attack? Seems a little overpowered to me.