For squirts and giggles I'll also detail -some- of the AI.
Wow. That's terrible AI. First of all it assumes way too much, and the assumption it makes are largely going to be wrong. Sounds a lot like a poorly implemented expert system, with little to no expert knowledge (everything it assumes). I can't see how this would be challenging at all. Free tip: NEVER use random numbers in AI.
Yup. It's an important aspect of game design that the choice the player makes has somewhat predictable consequences. The more you add randomness into the equation, the less predictable it becomes, and the more it becomes a game of chance, rather than a game of skill. The chess approach (playing through all possible moves to find the best one) is only applicable for chess games. For proper games you'll need a much more heuristic approach.