Haha i loved it as well!I sure hope so! It's my favorite mode to play in Zoo Tycoon 2 - it keeps me more interested in the game when I'm constantly meeting exterior goals. I really like how some of the challenges give you rewards for your zoo as well.
Indeed i also want challenge mode im not a fan of unlimited money i want to make a zoo from scratchI really hope so! I like the idea of just building my own zoo without campaign, but also having a limited resources, to provide challenge! If it will be only campaign and sandbox, I will be dissapointed.