Season 1 saw him battle The Reverse Flash, a villain in a Flash-like costume who pretended to be an ally, and Barry devoted himself to getting fast enough to stop him.
Then in Season 2, he fought Zoom, a villain in a Flash-like costume who pretended to be an ally, and then Barry devoted himself to getting fast enough to stop him.
Now in Season 3, he faces Savitar, a villain in an aggressively not Flash-like costume, who MIGHT be pretending to be an ally (jury’s still out) and then Barry devotes himself to getting fast enough to stop him.
As you probably gathered, this show got really repetitive, and any way they can shake it up is a win for viewers.