I seriously don't know how anyone can suggest Zekrom for bdif. It takes SO much to stay going. Right away it may not be hard, Tornadus increased the consistency for T1ing. But after the trick is pulled off, either attacking option is incredibly exploitable.
If T1ing with Tornadus, the damage dealt in only 80. Many pokemon survive that, setting up isn't difficult, and retaliation is also pretty easy with Yanmega and Reshiram, possibly two of the most popular Pokemon right now. Late game Tornadus is a lackluster Pokemon. Having lackluster HP and dishing out lackluster damage. It may help in charging up Zekrom, but you must still realize that it takes a bit of time, and time is much more valuable to your opponent.
Zekrom tears through more, but it also requires more energy concentration. When the initial Zekrom goes down, so do three energy cards. Having only 90 HP after attacking also opens up a lot of return KO possibilities with Magnezone, Boufalant, Reshiram, Donphan, Cinccino, and Zoroark. Late game Zekrom get revenge KOed by nearly everything. Any deck can do it. These decks can also retaliate much more effectively late game.
This is also not including decks that are not aggressive, such as Ross and Gothitelle, which I believe is commonly understood as negatives for Zekrom as well.
To my understanding, Zekrom beats a bad hand. That's about it. With people over teching their decks to such a large degree (Catcher should have told these player to not do this), I can see how it wins events. Especially after factoring that Zekrom is the most popular deck, and that BRs don't contain the best players. Thoughts?