They haven't released any information on the theme decks themselves other than the featured Pokemon in them (Druddigon and Giratina). As far as I can tell, they're going to be good for players getting into the game, but still only a mediocre stepping stone for teaching players how to build for competitive play.
I like the look of Lugia EX, that card seems pretty powerful to me and may be tested in new format decks !
Victini EX seems like a great support Pokemon for fire decks and other decks which require alot of basic energy on certain Pokemon !
Beware of the cuteness !
Victini-EX – Fire – HP110
[R] Energy Turbo: Search your deck for two Basic Energy cards and attach them to your Benched Pokemon in any way you like. Shuffle your deck afterwards.
[R][C][C] Rising Burn: 50+ damage. If the Defending Pokemon is a Pokemon-EX, this attack does 50 more damage.