I like the idea to use this card as a mill,however, I don't like it as an extra silence.You can prevent the opponent from playing any cards during 12 turns;It wouldn't be very rare to kill them before they can play any card at all.
If the player could not be forced to draw cards (Sanctuary), would it nullify the Silence aspect as well?
So if opponent has Sanc and you cast it on them? No, you would still be silenced - part of the cost (might lower quanta cost because of this).Or did you mean the original version (target is silenced)? In that case yes, they'd be protected from silence as well.
How would that change if it could target either player but would always prevent you (caster) from playing cards that turn?