So I take it in 5e there is no reflex defense (4e) or touch AC (3e)? A caster using a spell to hit a foe, one that requires a ranged attack roll, rolls to hit their AC? Does anyone else feel like this is a step backward? Not really a super huge deal, but I wanted to know the thoughts from others, or if I a missing someting (very likely scenario in fact).
A bunch of spells require the target to make saves instead of the caster making an attack roll. Magic Missile doesn't even require a roll. But spells that require attack rolls are against the target's AC.
I honestly don't care if it's a step backward. It works.
It's a simplification from the whole touch AC thing, but making a ranged touch attack always seemed like a formality anyway - it was rare for those to ever miss, and didn't really justify the time spent to roll them.
While a wizard does have to hit the full AC in order to affect anyone with certain spells (notably, most at-will spells - the cantrips), they actually have a pretty good chance of hitting. Since it's based on your casting stat, and everyone has the same proficiency bonus, the wizard is as likely to hit with a ray of frost as a fighter is with a sword.
Most spells (other than cantrips) are resolved with saving throws, though, and the chance of anyone succeeding on a saving throw is pretty low. Attack rolls mostly serve to keep cantrips in check. Mostly.
Nope, I like the fact that anything that is an attack roll is targeting just one number, it's nice and simple.
And I like the fact that wearing armour and using a shield is actually effective against alot of magical attacks.
I intially thought flatfooted, touch AC etc was a good idea, but got a bit tiresome in practice.
I did like 4E's 4 defences, but not so much I was sad to see them go.
In 5E If armour would help, then (Although there is a cool idea with shocking grasp which gives you advantage on the attack roll if the target is in metal armour)
If armour wouldn't help, it's a saving throw instead. Probably a DEX saving throw.
they simplified AC, which is a bad idea IMO, but they also "simplified" saves, 6 instead of 3 
for cantrips, I dont mind regular AC, but for regular slots I would like "touch AC" instead.
Touch AC was needed for a Wizard because generally they had horrible hit rolls since it used Strength for the tohit roll. Most wizards didn't have copious amounts of it to assist them in that attack roll.
With the new system, wizards get their intelligence added to the attack roll, making the need to eliminate armor from the equasion, moot.
Alynn wrote:
I don't see it as a step backwards. I see it as a simplification that streamlines Spellcasting along with the rest of the mechanics. As others have mentioned, spellcasters have roughly the same modifier to their attack rolls with spells, eliminating the need for a Touch AC, Flat-footed AC, Reflex defense, etc.
I do think that these additional AC options may present themselves as variant rules modules in future releases, but I don't see it as a necessity with the current system.
Either way...just my 2 cp
All good points, thank you for your feedback. I do not feel like this is a step back now. It simply works, and that is as it should be.