Warlocks kinda suck at the fiendish allies bit - they get only the top Conjure Fey and Elemental summons, plus the top undead spell, and Chain pact is kinda weak overall. Frankly, the warlock Blade and Chain pacts need as much revision as the Ranger does, but that doesn't change that they already exist. However... druids can run with packs of wolves - they get Conjure Beasts fairly early on, which is perfect for that. And there's rules for hiring people already for your Rogue and Fighter. So, no matter what we do with the Ranger, the others are already covered.