Ralph Fiennes wishes to avoid the villain roles apparently. He's honestly better off as Zazu therefore. Mark Strong, Jason Isaacs, Gary Oldman and Ian McShane are the guys perfect for Scar. Disney should definitely consider any of those guys. Ian McShane above all.

I made this before Ralph Fiennes said that he wishes to avoid villain roles.

I think that either him, Rowan Atkinson or Martin Freeman will work really well as Zazu.

I really want Benedict Cumberbatch, Jason Isaacs or Gary Oldman to play Scar. But I also think that Hugo Weaving, Mark Strong, Daniel Day-Lewis and Ian McShane will suit him as well.