adywan said:
There was a reason for that in ANH. If you look at the original FX the sabers have some really harsh jagged edges and the thickness changes due to the changing light intensity as the sabers move shining off the reflective strip on the saber. Unfortunately making them slightly fatter was the only way to cover them. But they are still nowhere near as fat as they appear in ROTJ. Boy those are going to be a nightmare to fix.

One of the things that I actually really like now about ANH:R are the thicker lightsaber glows.

They have grown on me a lot, now that I am used to them since my first viewing, and the original ones seem very weedy in comparison. And they ended up having an overall thicker look in ROTJ anyway as has been pointed out.