My hot take is that, to get around the "willing" issue, he could simply do the reverse of the Baby Theory. We know Dalinar plans to stand as his own champion, and so could Taravangian, personally, no tricks, not using his powers as a Shard at all.
He could try to force Dalinar to kill an old man who refused to physically fight him, a no-win situation that goes against Dalinar's oaths and all the principles he's been arguing about with Taravangian for multiple books.