I'm not talking about during their first draw step, though: can't they dredge immediately, during the resolution of Wheel of Fortune? Ie, they discard a dredger that was one of their starting seven, and dredge it to replace their first draw. They can then dredge up to six more times, if they had several dredgers in hand or get lucky with the library.
Oooooh yeah, I think they can actually. I don't think the Menedian Crew thought of that.
They addressed it (perhaps not explicitly enough about Dredge potentially binning half of their deck before they had a turn), but Kevin alluded to the possibility of just dying on opponent's turn 1 or 2 after casting a Wheel or Draw7 on the play and passing the turn, and his rightful hesitation to do so. To do this you either have to have a large number of mana floating, or the ability to Draw7 into something like Oath and cast it immediately before passing, and then plan on killing your opponent on the next turn. There are very specific reasons why/when you would cast a Draw7 against Dredge to open the game (such as a mulligan to very few cards, or a good amount of mana floating), as doing so can just get you killed if you have no follow up play.
The only Draw7s that Burning Tendrils plays that mitigate this are Timetwister and Diminishing Returns (out of the sideboard, if you run it), which will shuffle the graveyards back into the decks, but also leave your graveyard barren of a Yawgmoth's Will-fueled finishing move that turn.
