The young or cool look doesn't seem to bother anyone for other currencies (e.g. Doge).
Other currencies don't have the unique marketing challenge that we face -- that is, overcoming the stigma of being the "Dark" coin, and all the connotations that arise from this in the mind of potential users & investors.
If that is truly there case, then we need to change the name. It is earlier enough we still could. If being a dark coin is going to be such a challenge to get mass adoption, what is the point of calling it darkcoin?
Personally? I don't agree with a word I just said, because I also don't think we should be running from the idea of "dark" like you do. I don't think however we market it should promote that first and foremost, but at the same time it shouldn't be ignored. You can be professional and edgy at the same time.