I ran across this little nugget from Dave Parker on the FLL forums.
As a judge, I would like to hear more than "Bill made that one, and Sue made this one" from the kids, and hopefully also more than "This one has a light sensor, this one doesn't". I might ask "Why use the one without the light sensor, since it can also count motor degrees?". There may be practical answer, but I want to make sure the kids are on top of it.
I have judged at the state and WF (World Festival) levels, and listened in on many judging sessions at the local/qualifier level, and I would also add that in general, at the lower levels (e.g. qualifying tournament), design judges are interested in stuff you haven't finished yet (even attachments that are in progress), but at the higher levels, it moves to more of just what the final robot can do.
Having said that, at WF last year, one team showed me two robots, one of which was a redesign since winning their state championship, which was designed to go faster in an attempt to get more done in the time limit. After putting a lot of work into it, they still couldn't get it to score any higher than their original slower one, so they ran that one, but I was impressed that they tried and were able to explain the whys.