IMO this is because Scrabble is a terrible game. Knowledge of the breadth of your language will only get you so far in the game: the winner will be the person who can put the greatest amount of short words with 'X' and 'Z' in triple-word panels. If I were to re-invent the game I would remove the triple tiles and half the point value from most letters. This way you can give advantage to people who put longer and nicer…
Does the game in other languages assign the same point values to letters? Is the distribution of letters the same? It seems like a different language would have more or less frequencies of any particular letter which should influence the amount of available tiles and what they are worth.
There are always a couple of letters with extremely high scores, and the winning tactic is to play ugly short words with those letters by the multipliers.