The amount of gold you get from taking the [Touch] option from Face Trader goes down, but the odds of getting a bad face vs good face does not change. Source: I've worked on a mod before and if you look for it you can see the code for the event.. It's actually 40/40/20 (40 good/40 bad/20 caw caw). With which good or bad face you actually get being a 50/50 shot (+1 HP or +50 gold from ? rooms) the odds of getting specifically the Cleric Face is. a lot less clear lol. If I knew ♥♥♥♥♥♥♥♥♥ about probability I could probably help more with the specifics haha.
It feels like nearly every single time I choose to trade my face I just get that stupid gremlin face, which in multiple cases has boned my whole run. It's true that the "good" faces are really powerful to compensate, but in random-gen games like this taking a straight coin flip is almost never a good idea.. How good (or bad) are all the faces from the face trader event? Is the gamble worth it? Personally, I'm having trouble forming an opinion on this, and I've basically ended up going for the gold 9 times out of 10 rather than taking a risk on getting a bad head.