It's not just rebuilding engines it's returning their weight that's a problem. The high temperatures are a result of pressure not friction. A smaller and or less dense craft has a vastly easier time during reentry.

A shuttle actually works fairly well at around 1/5 the size. Lower thermal stress means no tiles. It would have a single ideally swappable engine large on board fuel and no external fuel tank. Still needs SRB's but those actually work fairly well.