Even considering as expensive as 23 set points for DW III, 12 for Triple attack. Some of the spells aren't that bad for base stat gain (worst of which is demoralizing roar) or comprise of spells we use in standard set already. There is a good possibility of getting more good spells blu will use in standard set for the trait also causing others to be phased out, but they may also be utterly useless too. Won't know unless they actually add it, if they do. Considering best possible outcome (yes, hopeful wishing considering SE) there is the possibility that is could be unbalancing to allow up to Tier III DW trait given the versatility of the job.

Negating a blink effect due to AOE is a little naive varied by situation also. Not every thing AOE's, and in most cases the same argument can make utsu just as useless. It wasn't meant in a spam circumstance, primarily a mitigation option, but not necessity just as Utsu is an option. Yes, it is still a blink effect, but it is more reliable then simply evading or parrying.

I can only see the loss of possibly Auto Refresh and battery charge, but typically I have a rdm to fall back on or at least a whm/rdm that refresh regularly (yes I know not everyone does) meaning the loss of this isn't a significant impact. This is assuming as expensive as 23 set points for DW III (all DW spells together is currently 18, and max spell cost seems to be capped at 5points thus 23) and using Triple attack trait set (12 pt for a total of 35 and 10 slots out of 20). Also, I can't recall even one blu that uses all the spells they set, over a select handful, while gaining traits from the rest so calling a spell that gives some stat bonus useless holds little merit since that can already occur in a standard spell set due to setting specific job traits.

Assuming the worst, we would end up with the 6th spell being -stats important to your major DD spells (similar to demoralizing roar) ending up with a total loss of possibly 8-11str or 4-8dex. The biggest negative to subbing war over the conventional /nin (or in some cases /dnc, /rdm) is the loss of more reliable shadows and subtle blow III. Depending on -mdt/-pdt gear sets the shadow part might not be a big deal given our newer spells, though the subtle blow could be. Not hard to swap into the appropriate set and use cocoon/defender to tank the hate off....or just keep tanking depending on situation.

Considering the options it can turn a mediocre sub into the new preferred sub while not necessarily hurting us and instead further improving the DD output blu is already capable of. By the way, you forgot Aggressor if accuracy is really an issue >.> Just saying....