I know this has been brought up many times before, but I figured I'd do a small test since I had nothing else to do.
Tachi: Ageha's defense down is allegedly 180 seconds.
I went out to Ceizak Battlegrounds and targeted Blanched Mandragora. (Incredibly Easy Prey with 119 level gear, Tough as a level 99 with no item level armor.)
My main hand weapon was a fully upgraded Amanomurakumo as it had more Great Katana and Magic Accuracy Skill on it than my Tsurumaru in case MACC meant anything.
Out of 100 Tachi: Ageha used, defense down landed on exactly 0 of them.
As a comparison I went and got my level 99 WAR with no item level gear on, a Terra's Staff, and only 304 skill.
On the same target, I landed Shell Crusher 12 times. I landed the defense down all twelve times, only getting a partial resist to the duration on 3 Shell Crushers.
I know that's a ridiculously small sample size but that should be enough to show that something is really wrong here.
I know Tachi: Ageha has a fairly acceptable landing rate on the test server, but on the player servers this WS has been broken, along with the added effect of several other WS/Blue Magic.
Can you please pass this along to the dev team and ask them to take yet another look at this?