Well I remember WAYYYYY back when (a month or two ago
), BigPoppaBeatDown came up with an Omastar Steelix deck with some tECh thrown in. Omastar was there to devolve the big guys Steelix couldn't handle, there was Electabuzz for late game (or possibly early) bench finishing-off.
BPBD declared the deck as being "chank", but I began to consider Omastar a more powerful card since then. It can devolve stage 2 evolutions, such as Blazy EX, and is out of reach, when at full health, of Blaziken EX's Volcanic Ash attack. It can KO Blazy EX with a strength charm, and gets out fairly quickly with the help of the trainer cards from Skyridge based on the fossil theme, not to mention its prevolution's attack.
Even only throwing in one or two is a good idea, as a limited form of tECh against pokemon relying on Rare Candy (Blaziken, Amphy, Gardevoir, and others) so it shouldn't do too badly against those decks. Running Omastar in a deck might not be such a bad idea. Even if only as a supporting guy, he can take a hit, with a BIG 110 HP, against non-infinite damage deck he'll live.
Just think about it. Really. Um.....are you thinking about it? Omastar could slow down BAR decks and Niniken decks, which Blaziken EX is included in. It could be a force in this format if played correctly, so contemplate its impact on different decks and see if you find it a worthy counter or not.