I think instead the 'Fist' stances should be incorporated as weaponskills that utilize MP. Monk has some points where Demolish can clip / drop and having a singular out-of-stance weaponskill would be useful here, without it being a DoT effect. Adding in the MP cost allows them to be impactful without risking them being spammed.

To spitball some examples -

Fist of Fire
25% of Monk's MP
Effect: Strike the enemy for X potency. For the next 12 seconds, Couerl Stance attacks also generate 1 Chakra.

Fist of Wind
25% of Monk's MP
Effect: Strike enemy for X potency. Grants Greased Lightning. For the next 12 seconds, Greased Lightning duration does not decrease.

Fist of Earth
25% of Monk's MP
Effect: Strike enemy for X potency. For the next 12 seconds, your weaponskills deal damage in a small area around you.