Well I don't know how much Roddenberry was involved this episode that aired five months after his death. Up until The Outcast
, Riker always had the same sexual tastes as Kirk.
I believe that we could perhaps evolve past basing attraction on appearance up to a point, but there will always be people who have certain types.
It depends on: How much of what attracts us to a certain person is cultural/learned? How much is physical? How much is pure biochemistry?
When we see humans romantically involved with aliens (such as B'Elanna's parents), they're always attractive, human looking aliens. You never see a human with a Tholian or a Nausicaan. We can change, but I don't know that we could change that