Magic Vs AC is Very Poor Reasoning

[Fifth Element]

It has nothing to do with realism, it has to do with simplicity. It looks like in previous playtests they had "mental AC" and that sort of thing, presumably like 4E's Fort/Ref/Will. I guess they figured that four seperate defences were a bit much, especially when you now have six difference saving throws.

Not sure I agree, I do like having different defences for different things, but I can understand simplifying it as well.

 

[Fifth Element]

I think spells that create physical energy effects that attack the victim's body should absolutely target AC. Plate mail absorbs and diffuses the heat from the burning ray so that it doesn't burn your precious pink skin. I don't understand why the game designers ever decided otherwise.

It's MAGIC!

But honestly, reading through some of the responses here, I think having just AC makes a lot more sense than I was giving it credit for. Some very good points made.

 

[the Jester]

If armor won't help overmuch against a given magical attack, you could always give the attacker advantage.

 

[I'm A Banana]

Sometimes, it's an attack vs. AC, when armor (or shields or suchlike) might help turn aside the blow, or when someone can dodge it.

Other times, it's a saving throw, when armor or suchlike won't really help you turn aside the blow, or dodge it.

So if you've got an effect that ignores armor, have them make a Dexterity saving throw instead.

 

[Keldryn]

Touch never really needed to be calculated at the table though. It was usually noted on the character sheet and was only fiddled with at character creation and adjusted as new items were acquired. So play was usually, "What's your touch AC?" which was a spot on the character sheet. Not much different than "What's your AC?".

Touch AC is another stat to keep track of on the character sheet. When you're looking at this issue in isolation, it is just a single additional number.

However, 3e took this attitude across the entire system, resulting in a lot of statistics to keep track of. Like flat-footed AC, it's another situationally-useful statistic to reserve character sheet space for. It also clutters up abbreviated monster stat blocks, where the ability to parse it quickly during play is very important.

3e's touch AC and Reflex save overlapped one another in concept but worked very differently. Collapsing both into 5e's Dexterity save cleans that up.

 

[eamon]

I agree with the general consensus that magic vs. AC is fine, both because it speeds play and because it makes sense to me that your armor/dodge would help you avoid rays and bolts and whatnot. Saving throws are generally reserved for area attacks-- if you're caught in the middle of a fireball, there isn't really a way to avoid it; you can just hope you can drop to the ground or curl into a ball quick enough to deflect the worst of the burn.

On the topic of the use of Dexterity Saves aka Reflex Defense aka Reflex Saves vs. area affects such as Burning Hands:

Isn't that actually kind of backwards? I mean, we've got an effect that covers a large area and can't be avoided by dodging, so naturally we represent this by... letting the PC's ability to dodge matter most and his protection in the form of armor not to matter at all?

That's kind of weird.

 

[JasonZZ]

I think spells that create physical energy effects that attack the victim's body should absolutely target AC. Plate mail absorbs and diffuses the heat from the burning ray so that it doesn't burn your precious pink skin. I don't understand why the game designers ever decided otherwise.

Traditionally, the wizard had a truly awful attack bonus. Letting them go for a much easier number meant that spells that required an attack roll were actually useful, instead of a waste of a slot.

And for the record, I approve of including armor in most/all magical AC attacks. Those that should bypass it (like, say, lightning vs. metal armor) should grant advantage in the appropriate situations.

 

[Remathilis]

This is basically how I feel about it too. In theory, it'd be great if you had an AC, a Touch AC, and a "denied Dex bonus to AC" AC. In actual gameplay, it's nice that you only have AC.

This is a microcosm of the difference between 3e and D&DN.

This.

3e is perhaps the most "simulationist" D&D ever. It has rules to simulate everything: Armor Class when armor is not useful. Crafting with daily progress. Wrestling Matches with pins and turnovers, etc. Its D&D when players say "It makes no sense that..."

Its also perhaps the hardest D&D to play for exactly that same reason.

It never bothered me that attack magic attacked AC in Basic or AD&D/2e. Its only 3e that touch AC became a core component (it was an option in Players Option). Its passing, along with the recalculation needed to keep 3 ACs, is not missed.

 

[I'm A Banana]

Isn't that actually kind of backwards? I mean, we've got an effect that covers a large area and can't be avoided by dodging, so naturally we represent this by... letting the PC's ability to dodge matter most and his protection in the form of armor not to matter at all?

That's kind of weird.

I've never been totally cool with it either, so in my games, I might change it to be a Constitution save. I'm all for making Dex (and Wisdom) less of an uberstat.

But this is one of the promises of 5e: it won't break the game if I do that.

 

[Viktyr Gehrig]

On the topic of the use of Dexterity Saves aka Reflex Defense aka Reflex Saves vs. area affects such as Burning Hands:

Isn't that actually kind of backwards? I mean, we've got an effect that covers a large area and can't be avoided by dodging, so naturally we represent this by... letting the PC's ability to dodge matter most and his protection in the form of armor not to matter at all?

That's kind of weird.

Yeah, it's kinda backwards... but Monks (and later, Rogues) are iconic for their ability to dodge attacks that couldn't logically be dodged. In an epic enough game where the enemy casts a spell that causes the moon to fall out of orbit, the Barbarian shrugs it off and has to dig his way out from under it with his teeth... and the Rogue just 'ducks' and lands on top of it somehow.

Just spit-balling, but with the ability score saves and the lack of class bonuses... I'd like to see each class, or maybe some classes, automatically gain Advantage on certain kinds of saves. Not for whole abilities, but against specific kinds of effects.

edit: Matter of fact, give Rogues and Monks an explicit class feature that allows them to roll a saving throw to ignore any area attack-- so armor is still more important for normal people, but implausible dodging powers are still intact.

Monks (and Thri-Kreen) could go further, getting the same saving throw against any ranged attack.