Ok, it seems that the option of activating Tor for .onion relays is the bare minimum we should do. 

The question is now, as a project, do we want to offer more privacy straight out of the box or not. 

I am leaning towards also using Tor for: 
1. Relays gathered from the Outbox model that are not in the user's relay list. 
2. All relays that require Auth (no IP-Pubkey link)
3. All DM relays

By default. 

More ideas are welcome.