I faced a problem of this kind recently in French about the "Historiettes" from Gédeon Tallemant des Réaux (1657-59). There was a -for me- unpalatable spelling for nearly all the verbs: "étoit" instead of "était", "faisois" for "faisais" and so on. At that time, they wrote O in place of E and you find it in litterally thousand of places. I decided to change all these occurences of verbs with O, just for the confort of reading...
It certainly is not an academic recommended change. Some could call it a barbarian edition but it gives ME more pleasure to read it as most of the sentences flow more naturally for a 2009 reader
