When using OAuth for authentication with EWS it like we can only use version 1.
i.e. https://login.windows.net/common/oauth2/authorize
Whereas the Office 365 graph API uses version 2:
https://login.microsoftonline.com/common/oauth2/v2.0/authorize
Are there plans to migrated EWS to OAuth 2 or deprecate OAuth version 1?
The required scope for EWS is only available in the v1 Azure OAuth endpoints, so you're correct there. The Exchange team has made no announcements regarding enabling this scope in the v2 Azure endpoints, but I can say that it is being considered.
I don't believe there are any plans to deprecate the Azure v1 endpoints.