I appreciate how much they fluffed Star Allies with more guest characters, but the base formula of that game looks incredibly uninteresting to me.
The game essentially forces you to utilize the ally/elemental powerup system to its fullest to get all the collectibles. If you play it like a normal Kirby game, i.e. as Kirby alone, you're getting a gimped experience and won't be able to access all the content. In Superstar and Return to Dreamland, having a party didn't fundamentally change the game but instead allowed you to experience it with someone else.
I'm glad that they're finished working on DLC for this game because they can finally put the whole team to work on the next one.