When a character plays the Pathfinding card, Pathfinding goes through the character's deck to find two movement cards. Unfortunately, the opponent can also see the process - i.e., the cards that are being gone through are revealed in the opponent's battle log. My opponent's wizard played a Pathfinding. Then I was surprise to see every card in his wizard's deck just popped up in my battle log as the Pathfinding flipped through the entire deck to find the two movement cards. I took my time to read through every log line to find out what cards were in his wizard's deck. Then I knew exactly what his wizard could and could not play. In that manner Pathfinding actually has a HUGE disadvantage: it can let your opponent find out your character's entire deck, it can reveal your character's entire deck to your opponent. I think it is an unintended programming oversight that needs to be fixed, ASAP.
That sounds like the right behavior to me. If you were playing with physical cards at a real table, you'd be drawing and discarding each card in turn until you found two move cards - and your opponent could watch which cards you discard in the process. What you describe is the worst case scenario - the move cards are the absolute last cards in the deck. You might also draw your two move cards as the first two cards if they happen to be at the top of your draw deck and reveal nothing else.
To me it seems wrong. In Magic there are cards that make you search your deck for a certain card, but the usual rule is that you then re-shuffle the deck after finding the card (so you won't know what's coming) and you do not show anything to your opponent except maybe the card you are searching for. In Card Hunter, there is no need to re-shuffle, because the deck cycles and discarding a random amount of cards has no major effect (it does have some effects, good and bad, but it doesn't kill you like it would in Magic). But as the OP says, showing your deck to your opponent is a terrible penalty. I would never play it in MP under these rules, unless I was sure my opponent knew my deck very well.
It might be brutal for a wizard, but honestly there isn't much variation in warrior and priest builds so I wouldn't be so paranoid about using Pathfinding on them. Warriors is basically "stack step attacks" (And if you've been doing that, it shouldn't mill half your deck anyways), and clerics are basically "stack nimbus and frenzy".
Even if that's true, it means Pathfinding will become a problem as soon as a variety of decks are viable in multiplayer, as is desirable. In fact, it's actually an argument against the way Pathfinding works currently. Look at it this way: it is desirable that unusual MP decks are viable - and therefore it is undesirable that Pathfinding is unusable in unusual decks.
I do not use Pathfinding myself. However, I think revealing your character's deck to an opponent is a severe disadvantage. I doubt that's the game designer's original intention for the gold card. Furthermore, Pathfinding's descriptions also do not even mention that your opponent may get to see your character's entire deck. That is a very important piece of information for people who want to play that card.
Your discarded cards always visible to your opponent so yeah, it's in the description. Beside, if Pathfinding reveals too many cards, your opponent has to scroll up to read them all. If he has that much patient, he could just turn the pause on play option on and gains access to half of your deck in the end of round 3.
I know it's in the description. But an alternative design for Pathfinding would be to just give you two random move cards out of your remaining deck. Then this wouldn't be an issue.
It's not a huge issue, because this information is already available if you work hard enough. If you go to options and select "pause enemy cards", then you can actually see the gear the enemy uses for each card they play (you'll end up clicking a whole lot more though). So after they play a couple of cards, it's possible to learn every piece of gear that they play (and then look it up on the wiki to see their cards). It's just a bit easier to do this if they play a long pathfinding chain, but if you really think this advantage is important you can get it every game if you really want to. In other words, by the time they usually actually play pathfinding, you'll already know most of their deck if you want to bother looking at the gear for every card they play.
Exactly right. Indeed, that method will probably tell you more exactly what cards they have available than Pathfinding, which will tell you the style of deck- which you'll probably know early on anyway- but not the cards that haven't come up yet. I don't do it myself, but it's pretty rare to get surprised "oh, they have that card" after the first turn. Back when I played a Volcano wizard, Volcano could get surprises because it's an card that doesn't show up much, but there's not many cards like that. A cleric having an Obliterating Chop or Touch of Death in hand can have that element of surprise sometimes. That's about it.