It doesn't ever have appeared to been looked at but has anyone thought about the grapics in DB3? I mean plain circles battling it out don't make the most engaging desktop display. I know it's easy to get engaged but from a newcomers point of view the simple graphics look like they came from a long way back especially when compared to the cutting edge photo realistic graphics today.
Now obviously you don't want to overload the graphics but there are lots of little things which could make a huge diffrence:
Dynamic shell and slime edges
Lets say you have some shell, to represent this a grey(or any colour really) line forms inside your cell, the more shell you have the thicker this line grows. The same for slime except this line is on the outside so the two don't overlap. this would also be a practical indicator as well as looking good.
Cell fill
Setting a semi-transparent fill for each darwinbot would be good as well, they look surreal when transparent but looking completely opague probably wouldn't look good either
Background
A customizable background colour which gradients light colour through to dark colour in pond mode, also a good indicator for the sun bieng down. Compliments semi-transparent fill also
Distinguishing
Finally it would be good if diffrent bot species could be more individualized. Rather than the squiggles inside set manually (not great in my opinion) designs could be set in the DNA even if the things are as simple as three circles, a triangle or a cross they are all definitle more eye pleasing than the default squiggles. You could even have things like cilia for distinctive bots or little spikes and mitrochondria (which could show as speckles).
Finally I'd suggest all of the above should be toggleable for performance over grapics for thoose who desire it.