[Haskell-cafe] return in Monad class necessary?

I wonder whether it is a typical mistake of beginners to write 'return' within a do-block (that is, not at the end) and if it is possible to avoid this mistake by clever typing. In a proper monad 'return' can be fused with subsequent actions, and thus it is not necessary within a sequence of actions. However, although sensible, 'return' is also not required at the end of a block. Has someone already thought about a replacement for monads?