It would be nice to believe there were two Joss Whedons - one who created BUFFY THE VAMPIRE SLAYER and his evil twin, the one who created DOLLHOUSE; one who wrote the "Serenity" episode of FIREFLY and one who wrote "Train Job"; one to love for "Once More with Feeling" and one to blame for the horrendous deus ex machina of SERENITY's 2nd & 3rd acts.
Alas, that is not the case.