The difference with Docs is that they are really sending a request over the network. We are just delaying the saving.
Whereas our savings are local and almost instantaneous (and might be synced later over the network).

For the user, I think "saving..." is misleading and it's not really easy to understand why it would take 2 sec.
That's why I tend to prefer "Modified".

Also, I would just hide "Modified" when the changes have been saved.