Unfortunately, it's not an acceptable answer in practice.

In my experience, users aren't clear what to do when presented with a free-form, multi-line text box in which they can enter their address. This results in frequent missing data – users aren't aware they need to include a postal code, or county, or country…

This is probably because users are generally conditioned to expect separate text fields for separate tokens in their addresses.

There's a middle ground though – extract the tokens you need (postal code, country) and allow the user to freeform the rest. And don't even think about trying to validate addresses in any real way – you'll fail!