[Shujin]

All of them are kinda weak-ok.

+15 str? Neat but not OPed considering how stats work now. But probably the best of the four.
+15 crit? Kinda cool for a crit build but not overhelming since you give up your torso slot (aka a Sarashi Gi could technically do the same and more when you dual wield something )
+15 evade? same as with the crit just that the sarasha Gi kinda combines both of them and dual wielding for a mage isn´t hard either.
15 ice damage when attacked(I assume only non autohits/goes against resistance?, never even tested it). Kinda...pretty weak. I would never even consider this on my ice characters, there are far to many better options. By far the weakest of them.

So in general I would say they all could need a little extra love since they are damm rare.
increasing the duration is a good start but still, even then they are pretty mediocre at best in my opinion.