I think we might mean two different things when we talk about balance. I'm talking about the balance across classes; the overall utility of the worst classes (Beastmaster Ranger and Four Elements Monk) isn't so low in comparison to the best (all the Wizards, Divination leading by a nose, and Lore Bards) that their presence in the party is a net negative. Sure, in past editions you didn't have as many customization options, but that didn't stop Wizards, Clerics, and Druids from being just flat out better in every way than Fighters and Thieves. Unless you intentionally set out to build an ineffective character; pick a race with the wrong stat bonuses and put your scores in the wrong places, a 5e character will at least be functional, and even the most carefully powergamed character won't be tremendously more effective than a bog standard one.
Fourth was a completely different kettle of fish. That was more about system mastery, and being able to sort through hundreds of character options to produce the most disgustingly OP build possible.
