The difference between `s` and `š` is similar to `s` and `sh`. Can you omit `h` in Englis? Well, tecnically yes, but you canged the language. Same on you!
What you could do is to replace an accent with an ASCII character. Compare the name of town Český Těšín with its Polish equivalent Czeski Cieszyn (Č → Cz, ě → ie, š → sz). Actually, this is how we got here, 600 years ago Jan Hus (John the Goose) added diacritics to shorten a few diagrams in written language.