Balance is overrated. As long as each class is fun I'm okay with it. I do agree that the Ranger is horrible in the PHB.
I agree that balance is overrated HOWEVER, think on someone who loves the class fantasy of a ranger, loves longbows, loves survivalism, loves the nature hunter archetype and wanna play 5e as one. Seeing wizards shaping the reality and stopping the time while he is completely useless is not fun or engaging. That would be very frustrating to him. Rangers could get some cool stuff, like the ability to imbue his arrows with nasty poisons, prepare deadly traps, TAME animals, i don't know, probably look to Dragon's Dogma skills which has the best ranger gameplay imo and translate then to 5e?
And yes, Sodark is right. You have tiers on 5e. The Godlike(Wizard/Druid), the Decent(Barbarian/Warlock) and the AWFUL (monk/ranger). I had a "5e doesn't need balance" mindset because all examples of games that tried to balance casters and martials based on D&D by nerfing casters made casters useless but now i understand that you can make Rangers better instead than the rest worse... On DDO, they even have a "solo friendly" thing on class creation, where classes with access to divine magic and martial powers are the most solo friendly, pure divine casters considered the second best, martial classes with no divine spells average and arcane classes the most hard to solo. The unique exception is warlock which is behind a paywall and nobody would pay real money to play with a ultra nerfed class. DDO doesn't follow much the P&P rules, On nwn2, is clear that martial > divine > arcane. With spell fixes mod, arcane casters become extremely stronger BTW.
Other problem that 5e has is that combats mostly on high levels are too tedious and is hard for a DM to challenge the player. Is not like on 2e, where a lv 1 necro can OHK another lv 1 necro and a lv 20 necro can OHK another lv 20 necro. In fact, everything has much more hp and everything deals much less damage than high level on previous editions.
Most campaigns on D&D rarely go above lv 10 and most modules only go above lv 10 when you leave Sword Coast. Eg - Descend to Arvenus which caps at lv 13.