The drop isn't guaranteed to go to him i guess, but I like him over neph. He should be doing way better than neph/mia on these stages, +2 move, on these giant maps, and he's got more 2range options than Mia. Boyd and Neph have level disadvantages to Oscar, and i think your underestimating the +2 movement with canto.
I think she was meaning to give them to neph, but i could be wrong.
Something else i forgot to mention is Oscar's earth affinity. This makes him way way way more durable than mia/neph when they don't get Ike's support