While I am disappointed that this is not Double Dash Mode,
, I think this is the best case scenario for us pricing wise. 8 Bucks at the highest for 1 of the packs. I think the general consensus was that $1 a track was more than fair.
It looks like these tracks will be fully integrated into the game, unlike say Theaterythm. They have there own cups and I be very surprised as such that they wouldn't also be available online even without the DLC. I'm sure someone will have to at least have it.
The extra Characters and Vehicles are just gravy and really show Nintendo making a Holistic DLC. Something that completes itself and enhances all facets. The only thing really missing is something new for Battle Mode. Which one of them if memory serves could use the new tracks straight up.
I don't think Smash Kart would really be a good title for Nintendo. This is the better approach and they'll probably have a new version of Mario Kart in a bundle initially w/ the DLC and then a Nintendo Select version probably around holiday 2015 with all of it.