Why are there so many i tiles in scrabble?

I played Scrabble and actually won for the first time in months today. One recurring complaint everybody seems to have is that the game has nine i tiles. Other than gerunds the letter i does not appear that often in the English language. Since there are only two g tiles I am not sure what the makers of the game were thinking. If English used i to make plurals instead of s it would be okay. But, other than cacti and octopi I can not think of too many plurals in English that use i instead of s.