Well, I agree that even the PHB material could have been designed better, as in it is not perfect. Some of the sub-classes are generally considered sub-par, and many of the spells are not really designed well. However, I feel this has always been the case for D&D since its very beginnings, and indeed all TTRPGs. That's kind of the point of them: take them and adapt them to make your own. This is not to say that one should excuse shoddy work, but TTRPGs tend to be more broad in design and scope; or at least D&D is trying to be so.