Okay, I'm saying that tank decks can still tank because if they run an EX of their own OR if they simply continue to run SEL, then Reshiram EX can never KO it. T-Tar and Legends are not the only cards to sruvive 150, the EX's can as well >.> And you're making it sound like Reshiram can do 150 every single turn under trainer lock and taking 160 damage from SEL (burn can still KO it, and Fliptini is cool but it's not foolproof for Reshi's recoil). Remember you're also giving 2 prizes.
I agree, if you want to make a deck based around an EX, you may be better of ditching the tanking idea. However, EX's will not kill tank decks and I predict tank decks will use them themselves simply to counter other EX's. They're easier to get out than SEL and have 160+ HP.
Not to delve too much into theorymon, but 600 damage within 4 turns is unlikely and still managable since 1.) SEL will KO Reshi and 2.) a normal field (say Blissey, Plume, Reuniclus, and SEL at the very least) can hold 460 damage before healing and without considering Dragons (or EX's to house further damage) OR giving up any prizes (And you're going to get 1 prize a kill as Reuniclus swaps it onto single prize Pokemon).
On the FLIP side, a tank deck like Ross.dek is doing 640+ damage (before burns) in 4 turns against Reshiram EX, a deck that isn't even designed to tank and must give up 2 prizes a kill >.>
