Again, the thermal protection system was delicate because of weight issues. If the shuttles design goal was to get 20 people to LEO safely and they had anywhere close to the same budget to work with they could have used a few inches of titanium as part of the thermal protection system vs just glued on tiles that are less dense than Styrofoam.
PS: The surface area to weight is directly related to reentry heating. A person can do reentry in little more than one of those old style space suits and a parachute, the shuttle needed something that was barely possible to build.
The wings - because they were wings - were vulnerable to debris strikes during launch.
Which wasn't important during _launch_ but was sure a problem during re-entry.