JUST A THOUGHT by a helpless sheith shipper but Keith piloting black was a bit too obvious in the trailer imo so my guess is this is a huge clickbait from the voltron crew and Keith is gonna try first to pilot black (shiro's wish and all) and probably fail in an incredible, very emotional, cinematic way
So, I’d actually love to see that. It would be heartbreaking but powerful to see Keith fail at piloting Black for the first time in attempting to lead Voltron. Like, I can see his head just not being in the right place yet, especially after losing Shiro for the second time. While we’ve seen his potential at becoming a leader, he also seems very used to being alone, and he’s never been forced into a position of leadership before (that we know of).
But I would also hate never seeing him grow into the leader he could be. I think he just needs to decide that for himself, because it was obvious he didn’t believe he could do it whenever Shiro broached the subject. The Black Lion’s Paladin needs to be the decisive head, after all!
Long story short, personally, I want to see Keith pilot Black and become leader in Shiro’s stead, just maybe not right off the bat. :D