I think that when color LEDS came out, people realized that they could now tint certain areas of the playfield, whereas before there was only one choice of light with incandescent bulbs. Instead of being limited in how the machine looks, some owners now could run free and color bomb the crap out of everything. And that's what people did. Go totally overboard with the whole thing. It seems like there is no moderation in how it is done. You never see subtle color in GI's. Its all or nothing. I will admit that I have a few blue LEDS in my Waterworld GI, and also a few in my BSD, but that's it. If it was done in all my machines it would lose something and the effect would not be unique.
I could see doing a light blue LED in the whirlpool area in a Black Rose machine. One. Not pink or purple, not behind the translite to try and intensify the color, not all over the playfield, but just one. Something done in moderation and knowing when to stop. Some people would not even do one led in the GI, but I do not think that would wash out the artwork on the playfield.
Another thing to consider is the theme. Champion Pub has an awesome playfield, and a unique concept as far as pinball machines go. I saw a picture of one that was clown puked in blue and green, and just blue and green. It does not give the feel of an old time bar, which is having unsanctioned boxing in its basement. It looks like black light mini golf. Or one of those old paper mache looking haunted houses from the 70's that was painted with fluorescent poster paint. It totally changes the whole look and theme of the game with color that is completely out of place. The sad thing is that someone actually thinks that improves the look of the game.