Well people can say looks dont matter to them but deep down you need something to turn you on, you need that intital attraction to draw you in. No matter what that "look" is, it can be a BBW, or it could be someone who is fail thin, if they are attractive and they catch your eye then yes looks would matter just a tad bit. I can say looks dont matter to me but what turns me on wont turn the next person on.
The last dom I talked with he was an Older white male with a jolly beard and I like that look, its comforting for me. I also like Tall black men dark skinned with muscles, as well as Light skinned black men. It just depends on my taste and if the attraction is there for them as well.
I truely do think personalitiy should be a key factor in looking for a partner, as well as trying to find someone who you can stand looking at. If you cant stand looking at them then it might not work out!