I think the problem with RGB is that orange and purple are not as saturated/bright as the rgb colors. I think you could adjust for this and reduce RGB, but I doubt anybody would want to do that. I know I didn't. Might be doable for a Halloween only show.
No doubt though, rgb is not a perfect solution. I recall not being able to create brown with RGB but never tried nor cared... I don't care what anybody says, the 8mm pixel does not have the output of a c9 incan either, MAAAYBE a low watt c7... Can't speak to led varieties. That said, there is a dual 5050 RGB c9 out and I bet it appears more promising. I also do not care for the milky (frosted) 8mm led and prefer the pure color from the 5050... The 5050 is nearly 2x brighter as well.
I will say this though, once I saw what RGB and incan together, I decided immediately to abandon incan. They just do not mesh well IMO. Since I had no color or led strings, I feel fortunate that I waited for RGB.