Some of the RPG to manga/anime seem to be pale in comparison with the original game. Well, that's how it seemed to me with Ragnarok, but I think it was a continuation of the manga.. not sure. ^^;
I would love to see an Anime adaptation of Chrono Trigger and Grandia II, though. They're in my top favorite RPGs that don't fall in the Final Fantasy series. Also, Secret of Mana 2 would be pretty nice as an Anime.
Chrono Trigger came out with an OVA, but it was more like a filler episode and you didn't even see the main characters' faces..