Heavy armour is not useless
I agree with the sentiment that when sticking to the expected point buys and the like, Heavy armour does earn its place as being useful. Depending on mobility for a high AC ends up creating a fairly easy to exploit weakness. Deny mobility, and you deny Dex / Dodge related AC. As a general case, the weakness may not be an issue, but it may need to be exploited only once to become painful.
Nightmare Scenario 1: Your stunned and exposed to multiple sneak attacks. You lose Dex + Dodge AC, and will take a great deal of damage from each attack that hits.
Nightmare Scenario 2: You get nailed by a spell that takes a way Dex + Dodge, and the caster has the support of mulitple archers. You are now goint to impersonate a Pin cushion until the spell expires.
Plausible Scenario 1: You get caught flat footed by an ambush manned by many Archers.
Plausible Scenario 2: You face opponents who inflict Dex Damage.
Plausible Scenario 3: You are attacked in a situation where you cannot use Dex / Dodge.
In these situations, even if the weakness is only for a round or two, and mid to high levels, you can get dog piled and taken down shockingly fast. For Plausible 2, your probably not as bad off since you just end up vulnerable instead of dead (low dex high armor opponent is just dead from dex damage before AC becomes an issue).
Also, If your bent on taking a class path that needs stats in places other then Dex (such as a Paladin which needs many stats to be good to get the best of the benefits of the class), Dex + Dodge may just be a non viable option.
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