Those retractable lightsabres were the worst. Once you snapped one off, as you inevitably did, you were stuffed. At least with the later versions if you lost the light sabre it was easy to replace (used to get a match stick and colour it in with felt tip pens to look like a light sabre and it worked just fine!)
Before someone says "cost of tooling, etc.", Kenner could have produced an updated ANH Luke with a normal hand and the lightsaber accessory developed for his TESB counterpart. Kenner modified R2--twice--one with sensorscope (TESB), and the other with the hidden lightsaber for ROTJ, so the company did make changes to existing molds / characters, etc.