two-factor authentication without to use a phone
In our country it is not at all safe to use a phone for two-factor authentication! Please provide the opportunity to use other services for two-factor authentication. Just not Authy! Otherwise I can not use your service, and many of my friends can not either.
If you cool-hacker you can easy use virtual numbers for getting sms lets say in US or UK. And connecting to them by VPN or TOR. Btw can you specify what another service do you want? Google 2-step?