Just give the option for both. Make it so if you select Taki and hit "A", you get no mask. Hit "X", you get the mask option. DOA does that with hairstyles and whatever.
SCII was indeed, largely because it was on Xbox, PS2 (most popular console of all time) and Gamecube (Link helped a lot).
Soul Calibur 1 was only on Dreamcast.
I think Soul Calibur VI will be the Street Fighter IV of the SC series. There are a lot of comparisons you can make between the releases of the SF games and SC games.
Street Fighter 2 was the most popular and iconic game in the series. Soul Calibur 2 is probably the most liked gsme in the SC...