Yeah, the Hyrule Castle stage was awesome in SSB64, and for some reason they brought back probably my 3 least favorite stages in SSBM. DK's stage has the text blocking your view constantly, Yoshi's stage is outright awful (Thanks, I don't like it when you stretch the screen even farther than Hyrule Temple) and Kirby's stage, while not awful, is essentially Battlefield with random wind.
I seriously hope they take the opportunity to bring back Hyrule Castle and Saffron City from the 64 game this time.
Also, I love the Yoshi's Island stage in SSBM. It's very different from most of the other stages in the game. Also, I fight in the middle pretty regularly and almost never fall into the hole. They seem to be picking the more unique stages from SSBM to bring back, with the exception of Corneria (which is just a great stage in general)