i think ricardo montalban would've still given the okay to Benedict were he still alive.
I imagine he would have done so.
Still, even if he did, it likely wouldn't have mattered to those who object to his being cast as Khan in the first place. It still
doesn't matter. Khan's a genetic creation, a person who was experimented upon in a science lab to create someone more advanced than the average human being. He could have been green with orange spots and it wouldn't matter as long as he's more intellectually or physically advanced in some way. That people take issue with it is likely because he's not Ricardo Montalban, it's not Star Trek II: The Wrath of Khan
, and this is not 1982. That's something the movie can't fix, regardless.