OK, a couple of things:
First: Definitions - call me stupid (or maybe the coffee hasn't kicked in yet) but I think it would be helpful for someone (& I'm looking at you Moon :) ) to actually clearly define what is meant by the terms that we are throwing around - WITH examples. I'm talking about the terms "exploding", "compounding", etc, etc, etc.
I think I can follow things, but I'm not too sure - and if there's one person like this willing to speak up then you can be sure there are at least 10 who aren't. :)
Second: you could use "^" and "v" for sort ascending and descending, respectively.
Third: You could change/add to a die field to do a string interpretation of what you wanted to roll ie record the roll as a string and then parse the string to produce the result. This would allow for relatively easy modification of the "string die" interpretation code to expand the system at a later date, if required. I don't know how to keep this backwards compatible - maybe the first cell of the diefield array could use a special character or sequence of characters to signify a "string die" that the original diefield code will ignore?
Forth: Red for rerolls actually makes sense, since it is being discarded. As far as other colours are concerned, I think you should make the decision and I believe we'll accept it - we do that for the Radial Menu Button and Category Ribbon Icons, so why not for this - FG belongs to SW, after all. For my own sake, as long as the colours are contrasting enough (see the rules on Heraldry, for example) and make some sort of logical sense, then I'd be OK with it.
Fifth: Instead of using "1" for success and "0" for failure, could you put up a "S" or an "F", followed by a number to indicate degree of success or failure. You could extend this to x[S,F]y for multiple successes failures (not at the same time, obviously) with y=the largest margin eg 3S7 = three successes with the largest margin of success being 7.
Sixth: For displaying on a UI diefield, you could use a small widget with the corresponding die phrase code (eg a "e" for exploding). Having said this, I'm not so sure you need to display this type of info - I mean, everyone who plays a given RPG knows how their die mechanic works, so it this necessary?
OK, enough for now :)
Cheers