The scoring scoreboard should follow a simple/minimalist, yet effective, design.
It should not take up too much real estate on the screen. Both the current scores and the time left in the match should be very easy to see with only a quick glance. Team numbers, the alliances, and the current match are also important, but do not have to be as large.
Another consideration to be made is that while HD is nice for recording the matches for later viewing, most webcasts are anything but. Therefore, anything on the screen
has to be easily discernible even when the video size is compressed down to small sizes for online webcasts.
I wouldn't include any additional information on the screen besides the above listed information during the match, because all it would be doing is potentially blocking one's view of the robots. Display all that information on the screen between matches.
Here's a quick mockup I made, using clean lines, large text, and partial transparency where it would look classy.
(Though regionals with lower-powered A/V computers for doing the chroma key overlays could probably just use a non-transparent black background in those areas.)
