This has already been done (http://www.adapplang.com/index.html).

Which is actually an April Fool's Joke. They only bothered to replace begin/end with {/} and is with :. Which results in delightfully asymmetric examples like with case:

  case Foo:
    when Bar => ...
  }

The also eliminated the need to both with and use if you use a package (the only positive change suggested on that site), and added some abbreviations like pkg and priv.