I'd love an Akshay Kumar interview this season, just in general really, but I think his reputation for being very low-key, spiritual and considered in his interviews (at least for the last decade) probably bodes him being a bit eye-roll as far as Karan's preferred juicy, snap-chat style of conversation goes.
I've seen them interact in a KwK style skit on Amitabh's gameshow, and in a talk/variety show Karan hosted in 2011. I had the impression they neither liked nor disliked each other, just considered each other mutually incomprehensible life forms. Not a lot of chemistry there. In terms of onscreen interviews, Akshay does better when he's paired with someone he gets along with, and can tease. Kareena, Katrina, Asin, Sonakshi, Saif, Riteish, John, maybe Vidya or Imran or Abhishek (whom he doesn't work with very often but seems to be friends with).
Him plus his wife would be interesting. She doesn't normally like interviews but is friends with Karan and seems to have rather a sarcastic sense of humor, to judge by her DNA columns.