For those of you who would like to do away with bumpers completely and return to the rules of 2006, the only way that I could see this happening is if FIRST developed a better way to signify which alliance you are on and did not care about robot damage. Round lights in early years were okay, but they were easily blocked by other robots due to their smaller size. Flags used in 2006, 2007, and 2008 came out to easily which can be fixed with a little rubber, but they also broke and were also small like the lights. Little led lights from 2004, 2005, and 2008 were way to small as well. Trailers in 2009 were awesome, but I doubt any of us would want to be stuck towing items forever in FRC games. My suggestion, 12 inch cold cathodes. Yes, they are a little expensive at around $6-$12 a set, but spending a max $24 (if you buy a pair that ridiculously expensive) will allow teams to either do away with or be creative with their bumpers and return to their team colors all while signifying which alliance you are on. Now I know that they are "just another set of lights", but they do work rather well on the field: note that they are much lighter in person and appear darker in the video,
http://www.thebluealliance.net/tbatv/match/2008iri_qm7
The overall goal of the bumpers are to create less damage to both the field and other robots. In the past two years with mandatory bumpers around the frame perimeter, damage to the fields has decreased and robot damage as also decreased. In 2007 and 2008, torn/destroyed bumpers were not uncommon along with metal to soft contact between robots. This desire for less contact between robots is noticed with specific bumper heights so that there is only bumper to bumper contact and no bumpers riding up on each other from varying height. Although this is a good idea, I personally do not like the idea of mandatory bumpers on the field. Giving the weight allowance for them is a good idea, but don't make it a mandatory item given the extent of rules surrounding them in past years.
The numbers on the bumpers should be of contrasting color to the bumpers, I don't think black should be outlawed, but a white or gray outline should be mandatory as scene here so that they number stands out from the bumper fabric-
http://www.chiefdelphi.com/media/photos/35535
Teams should also be wise in using larger fonts sizes and spacing the numbers out so that they are not squished and hard to read from 50+ feet away.
Just some of my thoughts!