Absolutely, and it's with the Google Apps/domain integration in mind I say it needs to be pushed out of beta and have Google commit to continuous development of it.

Now that the infrastructure is solid they need to continue to really drive and improve the user interface. It's still clunky with some searches and the interface can lag a little bit with the javascript.

Also, as I think about this, the themeing is also probably a step towards allowing Apps accounts to customize how the email looks for their domain and users. I hadn't considered that when I initially posted, and if that is correct that's a feature that will DEFINITELY help them push corporate accounts.