You got it completely backwards, Demon Hunters equaled Warlocks until they got fleshed out in Legion. Illidan's abilities in TBC describe him as a Destruction Warlock, he's flinging fire balls and shadow bolts and summoning demons against you 90% of the time:
https://wowpedia.fandom.com/wiki/Ill...rage_(tactics) Illidan uses:
- Flame Crash — Deals 1665 to 1935 Fire damage to the target and leaves a blaze upon the ground.
- Summon Parasitic Shadowfiend — A parasitic shadowfiend burrows its way through the target, dealing 5400 Shadow damage every 2 sec for 10 sec. When the shadowfiend is finished, it leaves the target and seeks new prey.
- Fireball — Inflicts 4590 to 6210 Fire damage to enemies within 10 yards of the target.
- Dark Barrage — A barrage of demonic magic deals 5400 Shadow damage to the target every 1 sec for 10 sec.
- Agonizing Flames — Deals 7200 Fire damage instantly to all enemies within 5 yards of the target and dealing 64800 Fire damage over 1 min.
- Summon Shadow Demons — Summons a Shadow Demon. The Shadow Demon will stun a target, then pursue it until death.
- Shadow Blast — Deals 7800 to 8200 Shadow damage to the target and any enemies within 20 yards of the target.
Plus, as is already mentioned, lorewise the Warlocks picked up the Metamorphosis skill from Illidan, which kills Warlocks = DH by itself.
Therefore Dark Rangers equal Hunters.