Quote Originally Posted by sayaijin View Post
So my DM wanted to "fix" the cantrip True Strike, but I'm worried it is going to be too powerful.

He's made it a weapon attack cantrip like booming blade, but it works with any proficient weapon (even ranged) and it gives +1d4 to attack roll.

The part I'm worried about is where he's made it where it the d20+d4 is equal to or greater than 20, then he's treating the attack as a crit and the attack as magical. Then he's giving it the additional d4 at 5th, 11th, and 17th so 2d4, 3d4, and 4d4...seems like an auto crit at 17th level.

He's saying it's balanced because it's still only ever one attack and martials would prefer multiple attacks, but there's a guy who wants to play Rogue...
You've identified the problem -- characters like Rogues do not prefer multiple attacks. Also, Warcaster exists.