Not really, since non-AC defenses are about 2 pts lower than AC (generally speaking), and the ranger gets an extra +2 to hit from weapon proficiency that implement wielders don't get.Keep in mind that Rangers virtually always target AC, whilst Warlocks are usually targeting the much more vulnerable Will/Fort/Reflex defenses. This way more than makes up for the only slightly superior die d12 type
Also, the warlock's damage is just plain awful and can't be improved, aside from some flat +1 dmg feats that are power-specific and hard to qualify for.
Astral Fire (fire & radiant): requires 13 Dex when warlocks need Int.
Burning Blizzard (acid & cold): requires 13 Wis when warlocks want Cha.
Dark Fury (necrotic & psychic): requires 13 Wis when warlocks want Cha.
Whereas weapon users get Weapon Focus: no prereqs, one feat, applies to all of their powers instead of only some. Rangers (and rogues) additionally can upgrade their quarry/sneak attack damage, while warlocks cannot upgrade their curse damage. And then the weapon users can spend a feat to upgrade their weapon dice, too...
+1 per [w], actually - which is great for rangers, who get to attack twice per round in most cases (which also gives them a double benefit from Weapon Focus and their weapon +). Note that casters don't have any equivalent feat.which adds only +1 avg. damage and was paid for with a feat anyhow.