I'd love to have Madame Gao back if she could come without mystical ninjas, but as that is unlikely, I'd rather have no more ninjas. (Except Elektra, of course.)

Alexandra/Elektra: not yet, I just checked. Otoh there's a lot of Foggy mourning and some good Jessica/Matt BROTP.

Recast: well, they could! There's always the traditional soap opera option of wherein he survives a plane crash and post operation emerges as another actor. Or just gets recast. If it was good enough for Rhodey...