DLC Pack 1+2 track tiers:
S+: Wild Woods, Big Blue, SNES Rainbow Road
S: Mute City
S-: Dragon Driftway
A+: Animal Crossing, Super Bell Subway
A: GBA Cheese Land
A-: Excitebike Arena
B+: GCN Yoshi's Circuit
B: Hyrule Circuit, 3DS Neo Bowser City
B-: Wii Wario's Gold Mine
C+: Ice Ice Outpost
C: GBA Ribbon Road
D: Baby Park
That's how it shakes out for me, anyway, and I'm pleased! Only one track I find outright dull and only two or three tracks I'm not that crazy about but can deal with. Everything else is gravy!
I'm still surprised by how much I'm enjoying Neo Bowser City here despite it being one of my least favorite tracks in Mario Kart 7. I can't pinpoint why...