The "default setting" for the 5e rules presented in the Basic Rules PDF is intended as a compromise between simplicity and customization options, and I think a binary skill system with a limited number of options accomplishes this. The proof of whether WotC hit their "modular complexity" design goal will be in the DMG: If it doesn't include a point-by-point skill diversification option that is, in total, neither better nor worse than the basic rules module, I think us skill-lovers will have a right to complain. But until then, I'm holding my fire; and my breath.