For Port Town Aero Dive (F-ZERO)
To my knowledge, the only new jam added to this stage was that sick arrangement that is Mute City Ver. 3. I rather like much of the music selection used for Port Town since it brings back all the Brawl remixes and uses tunes from F-ZERO X and F-ZERO GX. Unfortunately, two of the best songs from GX, Eight Guitars and Feel Our Pain didn't make cute and F-ZERO: Maximum Velocity had some pretty good tunes that aren't as recognized as the console F-ZERO games. There's also Mario Kart 8's jazz/rock takes on the series classic themes. Excite Truck music could also use more love.
For Zelda Stages
You have no idea how much it killed me to see Molgera from Wind Waker not return to the music selection for Zelda stages. There are so many great tracks from Hyrule Warriors that are begged to be used as background Smash music. For the Frog the Bell Tolls was never released outside of Japan, but stuff like that has never kept music from games with the same situation from being represented in this series, and considering its connection to Link's Awakening, I think including the main theme from that game would be appropriate.
For Duck Hunt/Wrecking Crew Stages
Duck Hunt's inclusion is Smash was a surprise as was Wrecking Crew getting an entire stage. Both the Duck Hunt and Wrecking Crew stages feature music not only from their respective games, but from other Nintendo titles and I love to see more tracks from other games make the grade.
For Wily Castle
I really can't complain about the retro medleys and those awesome remixes of Mega Man 1-3 music. But there was a missed opportunity to represent the spin off Mega Man games. I'm a bit surprised not a single track from Mega Man X or the Mega Man Zero games were included. I love the classic Mega Man series but there's far more to Mega Man than that.
For Donkey Kong Stages
There's plenty of jungle beats for the DK themes but if Tropical Freeze taught us anything, its that we shouldn't be afraid to rock out in the jungle. That game had a killer selection of rock and metal tracks and I'm appalled that none of theme were used in Smash.