Slight correction. There were some contractor engineers (NASA considers all contractors "junior" to themselves) at Kennedy Space Center who were worried about the foam hit, but were over-ruled by NASA management at Houston.
Another long overdue improvement: SLI engineers have eliminated the delicate and precarious heat-resistant tile system. Instead, they use lightweight "shingles" with nickel-alloy skins over ceramic-fiber insulating blankets to protect the orbiter and upper-stage boosters from the dangers of reentry. Unlike brittle tiles, the metal-skinned shingles can be bolted securely to the airframe.
Why not just fire up the assembly plants and do an updated derivative of the existing shuttle orbiter, with all-new avionics, using a titanium fuselage (with the enormous weight savings), and an ejectable crew cabin (re-entry-survivable) cabin with its own parachute system...and use this new-fangled Thermal Protection System approach throughout?
How soon could we get some hardware?