The problem with over-using the lightsabers in the prequels is that they lost a lot of their charm and what made them special. In the original trilogy, the lightsaber feels mysterious, an ancient and powerful weapon, only wielded by the Jedi (and the Sith) and you get a sense of how it's not a very common weapon, but only used by a few. The sparse use of the weapon also gave it more power, once they took out the lightsabers, you knew they meant business and that shit would go down. In the prequels, everybody.. and I mean everybody has a lightsaber, you even see classes of small kids practicing with them. Characters pull out their lightsabers as soon as they hear noises. It's just an excuse to throw more CGI into a scene overloaded with it already.
Giving everybody a lightsaber and giving them "reasons" for flashing them in every scene really killed a lot of it. If Luke had run around with his lightsaber out in all of the original trilogy, it wouldn't have been as special when he confronted Vader or the Emperor.
I also want to point out that adding more colors to them only made it more stupid IMO. Samuel L Jackson wants a purple lightsaber? I always liked the simplicity of the original colors. You had Blue which was sort of the apprentice Jedi, Green which was the master Jedi, and Red for the corrupted Sith. I understand Yellow is quite normal in the books/novels/games (whatever) and I think another "global" color could be cool, but seeing characters have unique colors only to themselves was kinda lame.