We have several systems hosted in AWS and utilize both MySQL RDS instances and Aurora RDS instances.  In my opinion you still need a DBA, almost daily I am still dealing with security tasks, performance issues, general maintenance, ETL tasks etc on our AWS instances.

There is then also all of the network security conundrums to solve when it comes to implementing VPC's, setting up ACL rules, VPN tunnels, security groups etc.  You should really be responsible for scaling your database platform as well which will require monitoring your environment, identifying when to scale up or scale out with replicas.

Our experience with Aurora is that is is much faster than the MySQL RDS option when it comes to small concurrent transactions essentially the usual CRUD type operations.  Where it fails is performing queries that aggregate large sets of data this is generally slower than MySQL RDS Instances.

First of all you do know that Aurora is based on MySQL? So you would need to port your DB from SQL server to essentially MySQL, depending on the structure of your database this can be time consuming.

2nd of all, how do you plan to migrate the 7TB of data?  That is an awful lot to transfer over the internet, although Amazon have now made it much easier with their database migration service :  https://aws.amazon.com/dms/ I wish that had been available when we started out.

Over the last 2.5 years I have learned a lot when it comes to networking which was never a strength working within the AWS environment,  and to be honest if you want to work effectively and securely with AWS you will need to learn it too unless you are already familiar.