Ultron got to Sokovia from Shield headquarters via the internet. Why didn't Vision follow the same path through the internet to destroy Ultron from within?
That way the Avengers wouldn't need to ever physically interact with Ultron.
We see Vision destroy Ultron's presence on the internet in a later scene shown below.
Vision could essentially take back all of Ultron's bodies, so to speak, providing Shield with an army, Ultron's army. 0:15 - 0:38