To balanced this skill they should add:
If your deck contains at least 2 machine monsters, your opponent can add to his hand SYSTEM DOWN from outside of his deck during any main phase.
This will ensure players will use this with Arcanas as intended.
There's already a lot of other skills for Sartorius that support Arcana Force, so the skill is functioning like intended. What is broken is Cup of Ace working like Pot of Greed. They could just put it in the Forbidden list.
If they want to nerf this skill, they should just make it work only for the first coin toss, and in case of multiple coins being tossed, this skill only works for the first coin. And the user of this skill will always go first in duels, they can't go second, unless the opponent also use Master of Destiny, in which case who start the first turn is decided randomly as usual.
Arcana Force players already has Right Side Up, anyway.
Master of Destiny being nerfed won't make Desperado players "use this skill as intended" with Arcana Force, they'll just change to Right Side Up if they really want to play Arcana Force.
They'll move on to other tryhard meta and AF players will have another option as a skill (sometimes you want the result to be tails for the monster effects).
Anonymous
Mah boi
