Mmn. Personally, I hope the reason they can’t form Voltron is because Black rejected Keith.
This has nothing to do with not liking Keith or wanting one of the others to pilot her, this has to do with Black’s agency. We’re looking at a Lion with a serious case of betrayal-induced ptsd. We just watched two goddamn seasons of Shiro having to earn her trust. And then he turns around and arbitrarily assigns her another pilot if he’s gone? She doesn’t get to choose? I can see her just going ‘fuck that’ and shutting down until they find Shiro again so she can give him a piece of her mind for messing with their bond like that. In fact, I’m really crossing fingers she does.