Nope. That would just make getting wins near impossible for arena decks.
Well, firstly, that implies that everybody would necessarily auto-quit if they weren't 99% sure they were going to win a match. I think that a) matches aren't necessarily that easy to determine against a good deck and b) people are prepared to have a challenging match (and would, often, prefer one to either a squash or a drubbing).
And, secondly, wouldn't an Arena win being hard to achieve make an Arena win mean something? Wouldn't you say that putting up a deck which ignores the Oracle card but which has a long-proven track record of doing very well in the Arena and then just leaving it there for 3 weeks makes getting wins so easy as to be meaningless?
Besides which, the potential gains for the person putting the Arena deck up are small compared to the potential gains for the person playing against the Arena deck. I think the bias should be towards making it fun for the person playing against the decks, rather than towards making it easy for the person putting the deck up.