Barry entering speed force for end of season 3 leaves it open for a new Flash to take over.
It would make sense for Wally West to be new Flash. They would have an opportunity to go deeper into his character and his ability to be a speedster.
I though Wally West was on sideline a bit to much for season 3. And I hope he gets a costume redesign too.
When Barry comes back hopefully you could see some cool speedster combo moves against bigger villains. So, we have to wait and see for season 4 until then run Wally, run.