I can't speak for any of the other games, but Tales of Phantasia is one of the worst games I have played for the SNES. The story, isn't too bad, but it's impossible to enjoy it when you are fighting one 20 second battle for every 8 steps you take on the map. Also, the controls for battle are severly unintuitive, and even though I was fighting a new battle every 30 seconds, I wasn't able to control my character effectively until the second half of the game. Also, the skill system where you have to use skills an obscene amount of time to master them and get new skills just encourages more grinding.
If they would have focused less on the soul-sucking random battles, which literally took up 80% of play time, and instead allowed me to enjoy the story and the characters, it would easily have been a great game. But it didn't, and that's why it sucks.