"If there was an opportunity to design a city from a blank slate"

Just stop. Your premise is both inadequate and dangerous. There is almost never an opportunity (excepting Barcelona's Eixample, Brasilia, and Dubai) to design a city as a blank slate. And when we do, it often doesn't age well, as conditions and transport technology change. Ie, Urban Air Mobility (UAM) is going to be a Thing in the future, but almost none of our present planning reflects that.

Read transportation history, and nobody planned for railroads in 1840--they invested millions in canals. Even after the Model T kicks off in 1908, it's not until 1919 that serious road planning starts, and not until 1957 when serious Interstate building happens. And never in those years did they think about preserving right of way for the metros and light rails systems that would be needed a few short decades later.

Further 'blank slating' even a district in an existing city is dangerous--from whence do we get the worst ills and failings of urban renewal. With an existing urban context, disjointed incrementalism really is best, but it does require planning to be a process to coordinate action, rather than steps to produce a document.