Sold, give the man a cookie.
I remember when I first saw the "you will be joining as an Engineer" warning when I tried to join a ship. I'd forgotten that I'd been gunner last match, and left that as my class. It was surprising and incredibly helpful, and I was relieved that it was added.
I like it. It'd give the cap a load more control over the match, though I do see the chance for some abuse with troll caps. Keep the notif if a joiner declined your loadout? Or else, you have to accept the loadout to join, and if you decline, you're sent to spectator?