What about region-of-impact effects for, say FoC and lock-up or random-location blaster deflection effects along the string? Or am I getting ahead of myself with the Arduino's capabilities....?
Certainly such gimmicks are in the realm of possibilities for neopixels, it's just a matter of programming. It's also not outside the Arduino's capabilities, but it's like with other aspects of lightsaber building: it's a bit about cram-fu, if you want to put in many things, you might run out of code space. But the situation is not so dramatic as with hilts (I speak from experience...:) )
I guess as people will start to build sabers with neopixels, we will see a lot of innovative ideas emerging, for code, for diffusing, for better supply concept etc. It's a new tecnology, thus plenty of opportunity to contribute.