God damn.
Flamethrower? Surprising? That's probably because Deoxys doesn't learn it in the first place. It would be awesome if he did, though. Outside of that, Superpower-less Deoxys is retarded. The real threat of Deoxys is that he can hit hard on both sides of the spectrum- no matter who an opponent sends in, Deoxys can hit that Poke fast, and hard (and super-effective). Otherwise, Blissey just laughs in your face. Grass Knot is stupid, as it only hit Swampert and bulky grounds (who are already hit pretty hard by Ice Beam). Shadow Ball is only for Cresselia- which is kinda stupid, as a D-E Shadow Ball can't even OHKO Azelf. Leftovers is stupid, as Deoxys needs to hit as hard as possible- besides, he's not going to survive long enough for Lefties to really be useful. And last, I love how you put Jolly on an all-Special set.
Blissey and Seismic Toss go together like a Heavy and Medic- perfectly. I can understand if you want to hit Ghosts, but without Seismic Toss, there's just so many other things that you don't hit- enjoy being walled and outstalled. If you're really worried about Ghosts, run Seismic Toss + Flamethrower. That way, you can hit the Steels that Toxic doesn't. By the way, Calm Blissey runs 252 Def/ 216 SDef, not the other way around.