Memorizing the words is necessary but not sufficient, there is still a ton of strategy and interesting dynamics to scrabble beyond the word list. The one that's most interesting to me is that at high level play it starts as imperfect information game but progresses into a perfect information game. At the start your opponent's rack could have anything, but once the bag is mostly depleted the challenge is not just to find the best scoring play, but to find your best play relative to all your opponents best plays for all possible racks they could have.