What I really don't like about either version of the deck is that half the time you won't get the card you really want when you oath.  By that I mean half the time you will flip a blessing with Rector and not have a Therapy in the yard, now that can be offset if you have one in hand, but still is a significant barrier.  With Witness half the time you won't flip Y. Will and are forced to Witness back something that is far less useful, at best you get Ancestrall, at worst you get Duress.  I really don't see why this has an advantage to a traditional Oath win (creatures) because the only matchup that is bettered is against a deck running large amounts of removal, and those just don't exist.

There is a card that can help the game against combo, though it may not be enough to win games on it's own.  Pyrostatic Pillar will be a serious pain for most storm based combo and can even push through enough damage to give Doomsday issues.  I think that a good combination of mana denial (Null Rod, Mox Monkey) and Pillar can certainly steal some games from combo.  The problem is that you need to board 4 to be sure you see it in your opening hand, otherwise Pillar will come down after they play out their artifact mana and a lot of it's usefulness will be killed.

Fish has plenty of other answers available to them.  They have Strips, Force, Daze and Stifle to hopefully delay long enough to get a 2cc spell on the board.  What worries me about Claws of Gix is the fact that it has an activation cost, so you are forced to use your mana to get rid of dudes instead of using your mana to play threats or counter their spells.  As far as answers go I really think that Spawning Pit is the best answer that fish has beyond just keeping Orchards and Oaths off the board.

I played Dragon for a while in 1.5 before it got banned and the worst part about playing Dragon is the prevelance or hate.  It's not that the hate stops you, it's that the hate is really annoying to play through.  I haven't picked up Dragon in T1 yet because there are lots of decks with the same type of power level but with a much lower number of cards available to hate it out.