How about a card that makes one trap square and two fake trap squares. Your opponent won't know which one is the real trap square.
I don't think so. Say you have a section of the map near your starting position with these. On round one you just move him adjacent to one of these squares. On round 2 you play the default card and all traps adjacent to the character are revealed. It just changes the order of movement for your characters. On maps with traps you want to move the Thief first to areas where traps may exist - he should have stealth/dodge cards to protect him for being in front. He could also have cards that detect traps while moving.
It still slows down gameplay because you have to spend actions just to check for traps. I don't think traps would really be a good addition to the game. So many other things the Rogue class could do instead. Like high mobility attacks, backstabs, smoke bombs, stealing cards, disabling / countering, and more. I could see the Rogue having traps in the sense of Laser Beacon -- throw something down on the ground and have it act as zoning.
Hmmm...... Decoy Duration 2 Tile becomes Decoy terrain. (Enemies treat all surrounding tiles as difficult terrain.) As though the decoy has a zone of control.
Yeah, I was thinking just "Caltrops: Burst 1. Difficult terrain. Targets who move through take 2 Penetrating damage per square. enemies who end their turn on this terrain take Penetrating 4 damage." Or something like that. There could be a lot of neat things you could do with a Rogue class... but I still think there's quite a bit of room with the base 3 to be expanded upon.
I think it is time to revisit the thief/rogue class. This game has gotten stale and a new class could inject some life into it Besides, theres already a lot of cards that could fit for the class. For example STEAL http://wiki.cardhuntria.com/wiki/Cards/Steal
While it would be nice to have a 4th class and 4th race, I doubt we'll ever see it. Jon and Farbs are working on another game. Hopefully they'll make an announcement on it soon. Maybe at PAX Aus.