One of the letters Franklin would have eliminated was the letter C. He firmly believed that where it produces the K sound, the world should spell K, cucumber/kukumber and where it produces the S sound it should be spelled S, cigar/sigar. To Franklin, this seemed entirely logical, but Webster thought such changes entirely unnecessary because English spelling rules took care of the problems.
The spelling rule is quite simple and is quickly learned and accepted by even the youngest students. When the C precedes the letters A, O, or U, it has the K sound (cat, cot, cut). When the letter C precedes the E or the I, it has the S sound (cedar, cider). When the C is followed by a consonant or is the last letter in a word, it always has the K sound., crumb, climb, panic, havoc. Almost no exceptions to this rule exist.
Interestingly, Spanish is very similar. Compare camino, cochino, and cuchara with centavo, and cielo. Also compare ciudad with cuidado. Spanish very rarely uses the letter K except in loan words such as kilo and kiosko.
The letter C is commonly used in English. Eliminating it would have played havoc with the digraphs and blends. I have often wondered how Franklin would have spelled church.