Scrabble doesn't get the credit it deserves in hobby circles. Competitive Scrabble is one of the most skill-dense games on the planet — top players have memorised every two-letter word, every Q-without-U word, and every high-scoring tile placement around the bonus squares.
The single biggest skill gap in casual play is the two-letter words. There are about 100 valid two-letter words, and most casual players know maybe 15. Memorising the rest instantly doubles your score in tight board states.
Two-player Scrabble plays differently from 3 or 4. With two, denial is a constant lever; with four, the board fills too fast for blocking strategy to matter as much.
