I thought a scruffy kinda guy who has glasses and always looks flustered...I dont know why...I'll bet Yelan would disapprove of him...
But consider this; if Syaoran's dad was someone Yelan would disapprove of, then he certainly wouldn't be married to her. After all, they are expecting Syaoran to carry on the family name, and to bring honor to his family, and how can he do that if his father is not powerful? I always pictured Syaoran's dad to be a tall man with a strong athletic build, and a very demanding presence about him. Also, he has to have magic, or how else could Syaoran be so strong at such a young age?