Exactly. Despite he now knows that not all dragons are bad, but he still personally prefer being around ponies, episodes like "Sweet and Smoky" pretty shows how different he is compared to other dragons in the show.
So it's kinda understandable why he have a crush on a pony in the first place because of his pony upbringing.
I somewhat agree with you on this. I personally don't see Spike having any interest in Ember or Smolder, despite being a dragon himself.
Spike seems to be more comfortable with the ponies then he with the dragons due to the fact he grow up with ponies all his life. So I don't see him moving to the dragon lands anytime soon.