In-game movies =/= cinematics. Cinematics are the pretty things where everything looks almost real and it's all rendered to perfection.
"Only players will know the difference". What do we give a shit about who doesn't know the difference? A worgen in body armour ripping pandaren throats left and right, now there's some Warcraft shit as we haven't seen for a while.
Why should their appear briefly? They're one of the most interesting races to see on screen.
And I don't think there was really any problem about the human handing a stick to the orc, I think the problem was that the pandaren actually survived after. A fat piece of blubber with no real weapons or fighiting experience beats a battle-hardened human captain and orc with HAND combat.