The ambiguity goes away if you write them as "все" and "всё". Diacritics, accents, umlauts and cedillas are useful; if you omit them you do a disservice to the reader.
Maybe so, but omitting them on ё is standard practice in Russian. A language learner who doesn't learn to deal with the ambiguity of the omitted diacritics will struggle to read real-world texts.