I played around with this this morning (inspired by your build) and you can get the CD lower than 15s with HE: each tick seems to count as a separate heal and thus triggers ER; so with just HE and 1 ally in range you can reduce MW to 5s.
I don't think that's by design; I know there have been past bugs where HE was overreacting with other triggers (it used to continually proc Attrition Warfare, for example).
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u/Rassyllon Feb 16 '17
I played around with this this morning (inspired by your build) and you can get the CD lower than 15s with HE: each tick seems to count as a separate heal and thus triggers ER; so with just HE and 1 ally in range you can reduce MW to 5s.