I do agree that out of the bat, this is a smooth iteration of previous formulas and have nailed the party kart genre. Handling feels great; after just a few matches the flow into drifts on winding tight corners are very doable.
Though i have a few things i would like to add to this conversation for the future of this mode. Many compare this being a direct relation to Mario Kart. And while i think that this mode is a great inspiration of this game, I hope there are some levels of branching out of the norm for its mechanics...
That's not to say directly with just adding more "powerups" or "kart selection stats" of that sorts, but implementing elements that work in the style of party animals for the track design and dynamic play. For instance, The Last Stand maps are know to each have a dynamic aspect that drastically breaks up the map in (initially) unexpected ways. Igor makes a good point of different pathways and obstacles, as this could be one, but to take it a step further would be to have events (usually in the form of a catalyst for disaster in Last Stand) would change the track as a whole to splice up the next lap per say.
Though this is a lot more work especially of a map of this size compared to the cookie cutter fighting maps, I look forward to seeing the PA team step out of the box here.
oh... one more critique, players seem very "split up". I don't know if its because i have only landed 2nd or 1st in all games (note I am just more experienced with racing games and could be a perspective from a better player), but sometimes i am so far ahead that there's not much action. I'm not sure if there's bots in some matches or what. It seems to me the item pool is more swayed towards boosts than rockets. but very little do i get combat opportunities. Maybe this is a good thing? If so there could be more of what I aforementioned.
A side-line idea that I would personally see that might fit well with the game's philosophy that i didn't want to include in my main part: take a spin on MK double dash with a more co-op or dueling aspect of the game. The ragdoll feel of the game is lacking in this mode...