wasn't so much talking about chancellor but more the effect itself... as in, how would it compare to other bonuses if you replaced current bonuses with it. Or what if it wasn't your whole deck, just "discard the top 5 cards of your deck" or something
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did compare it to other bonuses. let me list a few cards:
chancellor, scavenger, navigator, monument, fortune teller, cutpurse, woodcutter, swindler, nomad camp, bridge
all of them cost $3-4 and all of them are "+2$ *some bonus*" (except bridge, but you could rephrase it to so it had it too). you can directly compare all of them, by just ignoring the +2$ effect. you could also put moneylender on there... but people are going to start complaining when i do.
now, if i had to rank them spontaneously, i'd say...
swindler > cutpurse > monument > bridge > nomad camp > scavenger > fortune teller > navigator > woodcutter > chancellor
this list wont look identical if other people made it, but probably similar. this shows you how good chancellor effect is; scavenger does chancellor effect and more and it's still only about average. if you made "put the top 5 cards from your deck into your discard pile" it would be even worse. still, it's not useless, other cards are just better. it also shows how small the difference between $3 and $4 cards is.
maybe the "put deck into discard pile" effect would've been better put on a cantrip, maybe for $2. or you could combine woodcutter with chancellor (and make it $4). or you could just remove chancellor, cause scavanger makes it unnecessary anyway. either way, it's already done twice, it won't be done more, it's probably not done much in fan expansions either.
oh and there's a difference between "discard" and "put into your discard pile", because the first one triggers tunnel. if chancellor said discard, you would get 1 gold for every tunnel in your deck every time you played it.