There is absolutely no technical limitation preventing the addition of alternate hairstyles. The only limitation is that of resource allocation.
We have no idea how the engine works. I don't know if it's a technical limitation, but I'm willing to give BioWare the benefit of the doubt if it is, and accept their choices in their world if it's not. I'm not a video game developer, so I won't know.
Are you really surprised people are upset over a lack of CC options? The ability to design your PC to your own specifications is a cornerstone of BW RPGs for many. To them, it provides more immersion than any sort of realistic combat. Don't begrudge others their pet issues. They're just as valid as your own.
I don't really have issues, but that's not my point. I'm not going to be legitimately angry over a design choice. Miffed maybe. Even a little disappointed, but I'm not going to be angry. I just don't care enough, and don't understand when people do. Personally, I think the fact that we even get to make a qunari and that they spent the time designing a world that they actually fit in as a playable character is a step forward. Don't you?