It was LITERALLY overrated in terms of critic's scores. Some sources gave that game a perfect score, which is a joke if I've ever heard one.
It terms of the player base, it is probably closer to being rated as it should. It is a horrible excuse for a Final Fantasy game, but it is playable. It should have been a lot closer to a 7 or MAYBE a 7.5 than a 10. I don't think any rational people consider it to be a "great" RPG.