>>16748634GF has already said that Zygarde has been envisioned and designed entire years ago.
It is also acknowledged that Pokemon designs are produced at a scale that far outgrows the next gen that waits on the line. I heard that by gen1 there was already a pool of few hundred designs.
Therefore it seems quite likely that Gallade was ready around the same period as the 'original' Ralts family.
Although releasing him as a cross gen evolution caused some butthurt that lingers to this day, such discontent is still like a fart against the wind.
