As it stands, I think that Scrabble favours spatial and numerical abilities a bit too strongly, while not doing as much as it could to highlight and exhibit vocabulary and anagramming skill. In response, I propose two minor rule changes, one fairly trivial and one much more game-changing.
First, when a player has a word challenged, it is necessary that they be able to provide a correct definition for it, as well. If the word is in the chosen dictionary and they are right about what it means, it remains on the board and the challenger misses a turn. If the word placer fails either test, they must take back the tiles and forfeit their turn.
Secondly, double and triple word and letter scores are disregarded. This makes creating long words with rare letters more valued than normal.
A fair bit of experimentation will be required to determine whether these rules actually improve the game in the manner desired. Thankfully, there should be a fair bit of scope for that, since Emily and I are now equipped with a board.