So maybe asking about how to get better at hitting is the wrong question. Maybe a more profitable inquiry would be to figure out why so many aikidoka -- some of them very senior and very well respected outside the art -- view hitting as unnecessary. Start from the assumption that they *aren't* all clueless bozos, and see where that takes you.
You don't have to name names (though that would help for context, if you're so inclined), but is this to say that these senior aikidoka view hitting as never being necessary in any scenario within or outside of the dojo, up to and including self defense? I'm asking for clarification because the OP is putting a premium on atemi for effectiveness outside of the cooperative confines of much of modern aikido.
Setting aside arts and styles, if someone's not willing to at least do something common sense like stomp on someone's foot or poke an eye to help get out of harm's way and see the next sunrise, well, good luck with that.