To get a gentler reentry, you need a greater lift-to-drag ratio.
To have a better hypersonic lift-to-drag ratio you need significantly more wing area, which is dead weight (and drag and a control problem) on the way up.
Exactly! Re-entry is the transition from orbital dynamics to aerodynamics. If you want the transition from orbit to flight to occur at a lower speed, then you need to be able to produce lift equal to your weight at that speed, at the altitude where you will hit that speed.
That's one of the reason why space planes were preferred for so long. Bleeding of speed while skipping along the atmosphere and then coming in for landing.
To have a better hypersonic lift-to-drag ratio you need significantly more wing area, which is dead weight (and drag and a control problem) on the way up.