Yeah they are. I mean in some means, it will have almost as many new tracks as a new game would, assuming 24 new tracks come to the game. I think the reason why they're re-releasing it is that many people haven't played the Wii U version and they're just upping the visuals. I mean it's not a terrible idea to do just remake the previous stages anyway, it's kind of like less new tracks but a lot of retro tracks. Though I would like to see more brand new tracks, I guess it's their choice. Though it looks like we'll probably get a brand new battle mode and based on the Switch reveal trailer, there were two item slots on the screen, hinting at some sort of Double Dash mode.
I would call it Mario Kart 8.5. I definitely see what you're saying though. But especially with the DLC tracks, not many people played 8 compared to Wii and 7, so even less people played the DLC courses because not everyone bought them, and they're really good tracks, so at least those are wise to bring over to the Switch Version. But nothing has officially been announced yet, so who knows what it actually is.