I love IV to the death and I always will, but I'm having a hard time explaining why.
It just...grew on me, so to speak. I was fascinated by the premises and the introduction and I wasn't able to stop until I had finished it all, even if I had to put aside the other games I was playing at the time.
Why that? FF VI had better graphics, music and storyline and a bigger and more customizable party, so why?
I suppose it was a mix of different things, including the general feeling I got from it. FF IV is captivating in the way old epic stories were, it appeals to the archetipal part of me. And I loved, absolutely loved, Kain's charachter. From his looks, to his story, to his unrequited love and the way he switches allegiances and such. How both King Baron and Rosa loved Cecil more than him and still he tried to hide his resentful feelings out of his loyalty to both...Beautiful, grealty portrayed. Even by today's standards, but with much simpler means.