Didn't say it was a bad idea, just looking for a way to incorporate all of those cards into a deck and find a consistent way to play them proved to be in issue in my play testing. Mewtwo - Gardy is a great combo in psychic decks, but I think the Dusknoir line is too big to fit them in.
3-2-3-1 Dusknoir
2-1 Uxie
1-1 Azelf
1-1 Mewtwo
1-0-1 Gardevoir
1-1 Cresellia / Giratina
1-1 Dialga G
2 Unown G
- 1-1 Bronzong
- 1 Spiritomb
Is this the configuration you had in mind? Could remove the Azelf X.