I said more or less this already in one of the closed threads, but I will repeat: As a VAN fan, I hope they just figure it out and stay together. This VAN team will hopefully get healthy and play well down the stretch - they have excellent secondary scoring, so if their stars come back and come alive, they are a serious threat, even as a lower seed in the playoffs (no doubt in my mind they get there, considering where they are in the standings thus far).
But if there IS an issue between Miller and EP that cannot be resolved with them both staying, the main things to think about are:
1) VAN is in a competitive window, mostly thanks to Hughes and Demko's cap-efficient contracts, and even Miller's to an extent, if he is performing at his best, and with the cap going up
2) Miller has a NTC, which will kill his value - think something like Mittlestadt + 2nd or something, that's about all VAN could hope to get, imho
3) A futures return is largely unappealing - you would be banking on VAN's window being extended, and being most competitive after Hughes exits his prime, which is very risky. A return that extends their window, by acquiring players similar in age or slightly younger than Hughes but not years away would make the most sense.
So, to me, if a move is to happen, it would have to be something like this:
EP to CAR; Necas + Kotkaniemi + Morrow to VAN
This should appeal to CAR, as though they are sacrificing an excellent contributor, they are also adding what will likely be a premier prime-aged C to complement Aho and their still-strong winger depth, and sending back an inefficient (though not crippling) contract, while VAN gets a win-now piece back, a decent reclamation potential (that can be bought out for an 850k cap hit two seasons beyond this one), and a near-NHL ready player at a position of need.
It's possible EP could be dealt elsewhere, but the fit isn't very good (no teams I can think of who would give up a prime-age top 6 C for EP that wouldn't be a huge downgrade in the near future, it would have to be a Kotkaniemi, Mittlestadt or Cozens-type, and that isn't all that appealing to VAN without a Necas/Tuch/Lehkonen type +