Monsters can't make critical hits, and only "attack rolls with a Weapon or an Unarmed Strike" can crit. Suck it casters.
..... Ummm..... WHAT?
- Monsters being unable to crit is ridiculous and stupid by ANYONE's metric - Casters do NOT need any more nerfs.
Sorry, no, you can't have heard that right. I'm going to have to go watch that video now.
Reddit's repeated explanation for removing monster crits is that monsters have recharge abilities which suffices for the randomness. Plus, monster crits make it very (too?) easy and random to OHKO level 1 characters.
The exact line in the playtest pdf is "If a player character rolls a 20 for an attack roll with a Weapon or an Unarmed Strike...you roll the damage dice of the Weapon or Unarmed Strike a second time and add the second roll as extra damage." I.e., for sneak attack, smite, battlemaster maneuver, etc, additional dice aren't also doubled. For consistency, it makes perfect sense that spells wouldn't deal double damage because that'd be a lot of extra damage, whereas martials can add like 2d6 maximum (more likely 1d6 or 1d8) with normal weapons.
That said, I don't like making critical hits so wimpy. This is a huge nerf to rogues and paladins, a decent nerf to rangers, and even a nerf to battlemaster fighters. At least allow us to double our modifier to damage!