This spell is currently doing nothing in terms of raising minimum all skills damage.
Tested with Champ/Talisman of Might both on and off.
Max hit with Champ/Tali of Might (15% min all skil dmg - they do stack btw) was 690
Max hit with Empowering+Champ/Tali of Might was 690
Max hit with Empowering Water is 590
Although I gotta be honest, if Empowering Water 1 was registering its 100% minimum all skills damage bonus, it'd probably be way OP'd heh.
15% raises dps by about 16.66*%
It's sort of jaw dropping thinking about what that spell could do if it worked.
(incidentally I wonder if it relates to some of the ranger dps tuning issues you had)