A full-duration static fire would maybe catch some issues with propulsion and fueling, but then you're still static without the same free-flight vibrations, let

A full-duration static fire would maybe catch some issues with propulsion and fueling, but then you're still static without the same free-flight vibrations, let alone the wild maneuvering of flipping around a building with a backyard swimming-pool's amount of liquid in it. "Better tolerances" is a vague statement; adding more tolerances to all the things just makes the cost explode. Tolerance smarter, not harder.