I was wondering in addition to black-(color) crystals dropping off places such as Denova (black-orange) etc. that newer color crystals could be implemented as well, but not with a black core. I would be very much interested in seeing a mix and match of colors for a single color crystal, such as green-blue (green core) or the opposite, and the same could be said with other color combinations (yellow-green, green-yellow, blue-red, red-blue, orange-green, green-orange, etc. etc.) and just from this simple combination of colors, you can add an entirely new line of color crystals to the game, as well as several different combinations to satisfy every last person.
With all honesty, it would be a whole lot better if vendors ONLY sold you the regular color crystals (red, blue, green, orange, yellow, red) and then you would have to ask an Artificer if you want a black-(color) crystal as well as said color combinations I've stated above. This would bring much demand for artificers such as myself, not to mention I would be conflicted with which color combination I want. Just as a random suggestion, the said color combinations could just be crafted by choosing the color crystals separately (i.e. taking a blue +41 endurance and a red +41 endurance crystal to make a blue-red +50 endurance crystal) so the mats would still be used to create the starter crystals. I honestly have 5 full stacks (almost 500) Corusca Gems hoarded up in my bank, not being used because players can just go off and buy gear with the same exact stats, which brings me to my next suggestion.
Why can't Artificers make color crystals that have better stats than what anybody else can get from a vendor? Honestly, the last time I made color crystals and sold them were way before patch 1.1.5, when they were still +31 / 33 stats. I've talked this over with a bunch of friends and guildies, and they greatly supported the idea of having me make them their own custom bi-color combinations that would have slight stat increases over those given by vendors.
P.S. Just wanted to try to get some feedback from people who aren't on my server, and possibly with enough people backing me up, I could throw this out to BioWare's suggestion box and hopefully they'll take action depending on how many people would like this feature.