Not sure what you mean by the expected win. A binary is a delta of a call option the mid price is the approximate delta (if IV is the same). Delta can be used as a ROUGH estimation of probability of expiring ITM but that is not what i mean by perfect pricing. I am referring to the black scholes model of pricing the delta of a call = a binary price.

To see how “accurate the pricing” model of using price as probability you would need to do at least 100 trades at the same price and hold them to expiration. Ive done this and its spot on. Ive seen no variance in length impacting accuracy.

The only skew by trader sentiment is if 100’s of people are piling on a strike (like someone’s unmanaged signal service) and the market maker has to skew the iv in order to attract traders to take the opposing side to offset risk on a specific strike. This can be seen by seeing if the price of the exact same strike before and after a strikes expiration are both lower/higher than the strike in question. This is normal for any market maker who is obligated to provide liquditiy