Emotional dosen't necessarily mean "has the most deaths" IMHO. I thought FF6 was the most emotional, because I got really attached to the characters, especially Terra, and the emotional effect from their smaller tragedies and triumphs was multiplied by the sheer amount of attachment I had for the characters.
FF6 SpoilerWhen Terra's father fades from existence and when shadow dies, or even when Terra leaves her children behind to fight Kefka produced a stronger impact for me even though their deaths were not as dramatic as say .Aeris or Tidus . I gotta give FFX props for an excellent tragedy though, the character development wasn't quite as good as FF6 but it really was an excellent story, very atmospheric as well.