Hello all, and welcome to the blue skies of a Magic movie Dream Cast! Any actor (see Gina Davis' position on the usage of "actor", and her desire to retire "actress"), past, present or future (if you can somehow manage that; and if you can, what the hell are you doing wasting your time here?!) is fair game to cast for any role. You may also mention a selection of preferred actors for a specified role.
Without further ado, here are some of my choices, which will jump around storylines as I think of them:
I don't really care about actors not looking anything like the part they're playing as long as they can act it out well and it doesn't stifle representation which is already canon (ie making Teferi or Saheeli white, things like that).
Peter Capaldi as Urza would be interesting. I think he could pull that off.
Melissa Marsala as whatever, just put her in the film, Jacqui needs to be appeased.
I don't follow many actors' carreers so I can't comment on most choices other people made in this thread but I'm skeptical about Jennifer Lawrence as Jhoira (I'd rather they picked someone who could be funny but also more intimidating, perhaps like Maggie Smith but younger, I can't think of any examples though; or perhaps someone like Claire Foy) and I think Terry Crews as Militia Bugler would be basically a cameo role and thus not really worth it, if they put him in the film he'd be better in a more prominent role imo, I'm sure they could find other actors for the Bugler.
Also, apparently WotC itself (or at least the Arena team) signified that they want Phil LaMarr as Teferi by having him redo all the v.o. for the character, and I'm not sure how I feel about that, especially since they don't actually give credit to any of the voice actors, either originals or replacements.