We should simply say that Khan is Sikh, but is not practicing, or that he is but is not particularly committed to his religion.
No. Both sides to the question of whether Khan is Sihk have plausible arguments. Since it could go either way in canon continuity without introducing more problems than were present in
Space Seed regardless, we won't know unless and until it's mentioned on screen in a future episode or film.
To get hung up on his lack of facial hair or a turban is to be rather pedantic in defending the decision to cast Benedict Cumberbatch in the role,
Agreed. Since Khan claims that Harrison is an identity invented by Admiral Marcus, it would be reasonable if his entire appearance was altered. This has been pointed out many times on the board already.
when they should have made at least some minimal effort to cast an actor who resembled Ricardo Montalban, considering that, as others have pointed out, the two Khans are the same person.
No. That is to say, Cumberbatch was not miscast. If you don't think he looks enough like Montalban, see above.
It is all a problem resulting from this whole parallel timeline nonsense.
No. That is to say, most of the parallel timeline episodes of
Star Trek have been excellent. Since parallel timelines are a standard trope of
Star Trek, one can't say that it is intrinsically nonsensical, unless one also finds these other episodes which comprise a lot of canon continuity nonsensical as well. Orci et al. simply elected to handle the problem of how to move forward via the
Star Trek way. It's super-hard to fault them for handling things in a way that could be reasonably characterized as the
Star Trek way, since it's
Star Trek.
Though I was opposed to the idea of "rebooting" Star Trek in the first place, they should have simply gone for a full reboot instead of half-assing it the way they have.
So, you are recommending that they should have done something you were opposed to. There's just no pleasing you is there!
Abrams, Orci, and the rest can't say they were concerned about the fans taking issue with the idea of a full reboot as since they took over control of the franchise they've made perfectly their disdain for those fans who would care about such a thing.
I don't make it a habit to put words in peoples' mouths, or to read people's minds, so I can't say what they can't say.