Balance, in general, is severely overestimated in terms of importance in D&D - and for that matter, any other human-run tabletop game. Despite claims of a "rule 0 fallacy" where the game is thought to be inherently unbalanced if the DM has to intervene contrary to the rules, in reality this "fallacy" itself is a Stolen Concept Fallacy - the entire GAME is designed to be run by a human who can adapt and change things. Rejecting this in order to focus on the letter of the words is selectively rejecting one aspect of the system while accepting the rest and then complaining about a problem that creates. While this can be true for a particular campaign or game group, it's based on the idiosyncracies of that group and how it plays. A game group that plays exactly according to the rules as written and allowing every official supplement but no house rules or third party supplements at all is a theoretical standard and reflects how almost no one actually plays, much like balance comparisons at level 20.
That said, it is important for each character to feel useful. This, however, is the job of the DM. Don't allow characters that can do anything to do anything. If you have a rogue with good lockpicking abilities, don't grant the wizard a 'knock' spell in random loot, for example. If he really insists on buying one, ask why. Point out that if he's using it he may be taking away a major role from the rogue. (Note I'm not being edition-specific here, but talking in large generalities). Tabletop games are played with friends around a table. If one person is insisting on doing things that make the others obsolete the problem isn't with the game system it's with him powergaming at the expense of friends.
If a player insists on making an ineffective character for roleplay reasons, people should explain to him that he'll... be ineffective. If a player is inexperienced, others should take him in hand and show him how to avoid pitfalls of character creation, and the DM should be generous in allowing reversion of choices for the inexperienced.
Balance is about balance in your group. Sure, some rules are ill-considered, but mostly the problem isn't the systems; it's the people that want the system to compensate for their poor social skills.