Elude, Kuji-In, and Overload are fine. They put everyone over the defense softcap (remember, balance around average SO builds that may not take the Fighting pool), boosts recovery, defense debuff resistance, and max HP in Overload. They do exactly what an ultimate defense-based armor power should do -- making you nearly godlike for 180 seconds.
Strength of Will is a bit of an oddball power in an oddball set. Willpower is hodgepodge of resistance, defense, and regeneration. You're not supposed to have massive numbers in any one of those areas, so the relatively low resist boost of SoW makes sense, and I think is balanced out by the low recharge time. I wouldn't object to adding in a small +regen/+absorb and +defense. Unlike most other T9s it doesn't make you godly, it just gives you a boost. One With The Shield is in a very similar place in a set that's also a mix of various damage mitigators.
The only T9 I think needs a major retooling is Moment of Glory. It grants abilities that shouldn't be in a healing-based set with a duration that makes it mostly useless.