Oh you are quite wrong. *Time for Yun's nagging sesson*
According to Book of Relationship and CloUdiSm Remix III, the best
form of physical looks that one should desire for another partner
is not more than 1 or 2 points difference. This is the reason why
people will choose parterns whose overall looks factor are the
same. 
However, this is not always the way it works. Self esteem,
confidence, karmic relations, personal character adds up to about
75% importance. Look on the street and you will find couple of
average looking guys with stunning babes.
Why you may ask? 
In warfare of Love, first Law of the Art of Seducation, everyone is
either seducing or being seduced. There are 18 differents types of
victims and 9 different types of seducer, each with its own
strength and weakness. They are people who will tend to fall for
that kind of seducer because of two reasons. 
I) Childhood psychological and 13 - 26 years of environment
influence.
II) Astrological, spiritual, karmic relationship with that
person.
Ok, I am going off topic. However bad their character is,
their looks always seem to be able to cover it up for
them. - it highly subjected to individual basis, but for
my case, I see no reason why their looks can cover-up - the risk
factor category of people will be probably react in this way is
people who worship girls (definition - treat girls better than guys
a thousand times (Flaws of Inequity) - not neccessary buaya.) Well,
for me, I don't believe in pretty girls must have such benefits -
if their character suck, probably I wouldn't even give in to them.

Everyone wants a good looking gf/bf with great character, no doubt.
The key thing is that are you able to get them? Desire and reality
is two different thing: if you are able to - I say go for it,
because when you found a good one - its unlikely you will drop
him/her for another potential - then everything has to be depended
on how this relationship is being led. In theory, this will greatly
reduce the chance of failing in the relationship - however it best
to be work in two ways (she preceived (highly subjective) you are
good looking and same other way round.), but in reality: it isn't
so perfect. 
Cheers