I not too sure if they are unpopular or not but.
Firstly, I prefer Gangrel to chrom. ( I feel Gangrel is a person with actual emotion and motives compared to chrom who just generic Prince number 174.)
Secondly, if not for Gangrel I Wouldn't marry my female avatar to anyone. (I don't mind Libra and lon'qu but I still Would not marry my avatar to them.)
Lastly, the less i say about female characters the better. (Don't mind emmeryn or anna but not enough to marry let alone play the male avatar.)