Currently enchantments mods “%of focus/stamina/health on damage dealt” apply on every single hit of multi-hit Runes, like Spin or Dual Flurry, causing them to restore 30-40% focus/health/stamina on use, with no more than 1 mod on weapon, for respective stat. This provides these Runes infinite sustain on bosses and trivializes fights. It also gives advantage to these Runes over hard-hitting 2H ones.
I suggest changing behaviour of these “on damage dealt” mods to apply only once per use of Rune attack. This will mean they are still usable and can be build around, and maybe even provide similar benefits if heavily invested into.