We did both 1900 Park Fare and CRT (twice, actually) on our Honeymoon and we're doing 1900 and CRT (only once this time) again on our anniversary trip. Honestly, they're so different I don't think they compare.
CRT you meet Cinderella for like a minute, and then have your meal with the other Princesses. With 1900, you have dinner with Cinderella and the other characters from that movie. The feel is different as well- CRT is very...special? You're in the castle, the theming is gorgeous, you are served dinner. It just feels very much like being in a fairy tale.
1900 is a lot more laid back, and the surroundings are gorgeous but not quite as fantastical as in the castle. You go to a buffet (more food choice!) instead of being served. Plus, the Step family is there and they alone are worth the reservation. Not to mention it's the only place to really meet Prince Charming.
So no, I don't think both are overkill.