This is true. It's also bad design even if it is nominally balanced, because it is balanced in exactly one type of campaign: the one where you start at level 1 (where the Wizard sucks) and progress to level 10 (where the Fighter sucks)*. It's not balanced if you start at high level. It's not balanced if you stop at low level. It's not balanced if you don't progress (a la Conan or Superman). It's limiting the number of potential campaigns the game supports for
no reason.
*: Obviously, simplified to not use AD&D advancement.