The one rules hurdle that I did encounter was a situation in which needing to roll attacks slowed down combat.
I've posted about not using attack rolls before. And since that post, I even found a post on B/X BLACKRAZOR from five years ago that talks about the same exact thing. I would recommend both posts. Though this post will be the only of the three that deals with a specific case in point.
So in this 5e session, I had the PCs exploring a small dungeon. They came to a hallway, one side of which was blocked (for the sake of combat), but the entrance was open. The players walked past three puddles of gooey salt, which began to rise up and form a disgusting kind of undead, which then attacked. These undead were based entirely on the standard 5e zombie monster, except their attacks dealt +2 damage against opponents they had already struck once, due to their slightly acidic bodies.
Which is all to say, they had an attack bonus of +3 and an AC of 8....
The combat was relatively interesting, but just before it finished (and two PCs had hit 0 HP thanks to the difficulty fighting in a tight hallway), there came three rounds in which the paladin and the zombie thing he was fighting missed each other with every attack.
On the first round that this happened, I did my DMly duty and described what had caused the misses as appropriately as I could.
Zombie misses: "The zombie creature is slow, and now that the other ones are dead, you can focus on this one's attacks and you dodge the slam easily."
Paladin misses: "You are trying to end this fight as soon as possible to help your friends, and for a moment, you get ahead of yourself and swing your greatsword above your head for a heavy strike. However, the low, stone ceiling of this dungeon hallway catches your blade and stops your attack."
...but then they both missed again. AND AGAIN! WHAT?
How can I describe that? Does the zombie slug monster dodge the attack? The thing with an 8 AC... evades? No. That makes no sense.
If this were a one-in-a-million thing, it would be negligible. But it isn't one-in-a-million. The average AC of the PCs was about 15. That meant the zombies needed to roll a 12 or higher to even touch the PCs. That's a 55% miss chance. Meanwhile, the Paladin had a +3 to attack rolls. That meant he should have hit a lot. On any roll but 4 or less. But in those three rounds, he rolled a 2, a 3, and another 3.
This is not a lone case. I have experienced many combats which had rounds where almost NOTHING happened thanks to the to-hit rolls being low.
So, let's speak on the game implications of not having attack rolls. In bulleted list form, for your ease of use:
- No attack rolls means the only way to distinguish who is accurate from who is not is through narration and description, i.e., if your character deals no damage with a few of their attacks (say, from armor or shield damage reduction, or some such mechanic), then the GM may choose to narrate those attacks as misses rather than hits that were deflected or not hard enough.
- Spells which have particularly meta-game effects, such as true strike and blur, which modulate chance to hit, either have to be changed to modulate damage instead, or removed completely.
- Time at the table will be saved. That's just a given, since only about half as many rolls are being made during each encounter. The B/X BLACKRAZOR post speaks largely to that point.
- No attack rolls or bonuses makes it harder to distinguish between different types of monsters, as there can effectively be no mechanical difference (as far as singular attacks go) between the inaccurate but strong brute and the precise but only moderately strong skirmisher.
- The relationship of level to combat accuracy/power has to change a lot. Of course, if you use Relative Level instead of Objective Level, that problem goes away. *poof*
- Monsters with multiple attacks will need to be scrutinized so they are not too hard to defeat.
- Magic weapons cannot be relied on for their mechanical bonuses to accuracy to scale encounters. Instead, stronger/tougher monsters would have to resist or be immune to non-magical weapons.
- It makes the fighter's job less important, in that it no longer gives them a complete monopoly on combat. They may still have the highest damage with weapon attacks, but other classes are just as capable of attacking.
- Armor and other protection now become much more valuable to players, because they are the only things standing between them and a toothy demise once that 50% get-out-of-jail-free-card is no longer in the game. If a goblin with a knife runs up to you and you are unarmored, you are in trouble, no matter who you are. Of course, if you survive the attack, then the goblin is certainly in trouble.
- Which is to say, combat is decidedly more deadly, but still within the control of the players. Random spikes of damage should not be as big a factor in character death as simply choosing to continue or initiate fighting when you are not up to the challenge.
- And perhaps most importantly, it brings combat into a certain philosophy about dice rolls: if the two options when rolling a die are either success, or maintain the status quo, you have created a false sense of conflict. Dice should be rolled ONLY when someone is going to win or lose. If a possible outcome is "nothing changes," then why were those dice even rolled?
I'll do saves tomorrow, I think.