This isn't important but I'm happy. After hundreds of tries with the masuda method I have finally bred a shiny mudkip. It is my favorite pokemon and I named him Purple! Now that I got him I'm not sure what I'll sink my time into sun for now.
Diancie is a mythical that was given out only for a promotional event. If you lose a mythical your basically screwed unless it gets offered up via promotion again or you can obtain one through a trade. Or, you want to pay some shady website for one.
They collect discarded ideas and plan to reutilize some of them better in a future when it's more functional and pratical, yes
As for technical side...absolutely not, they are always 2-3 gen late with graphics and all ( like I wrote in the thread about developers stuck in the past) and this, as long as GF will develop pokémon, or something from up floors specifically commando them to evolve technical side of their games, will never change