There's a very good review of what it takes to build a state-of-the-art AI Scrabble player in the following paper (appears to be open-access, apologies if not):
There's more to it than you might think. In particular, I was initially surprised about how much of the game is about rack management. Although I know this won't be a surprise to people who've played Scrabble seriously.
World-championship-caliber Scrabble, Brian Sheppard, Artificial Intelligence, 134(1–2):241–275, 2002. http://www.sciencedirect.com/science/article/pii/S0004370201...
There's more to it than you might think. In particular, I was initially surprised about how much of the game is about rack management. Although I know this won't be a surprise to people who've played Scrabble seriously.