The Flash Season 4: 7 Theories On How Barry Allen Will Return
2. At One With The (Speed) Force
One outcome of Barry Allen's stint in the Speed Force is that he could become a much more powerful speedster.
Turning again to Wally West's experiences in the comics, when Wally returned from a spell in the Speed Force he became much more at one with the Force (no, not that one) and could syphon energy directly from it like no other speedster could before him (even Barry). In the TV show, Barry could be granted this ability and truly become the Fastest Man Alive. Plus, with the big bad of next year confirmed to be a non-speedster, there won't be anyone to challenge him.
It has become a running joke with fans by now that, though Barry constantly calls himself "the Fastest Man Alive" at the beginning of every episode, there are at least four or five speedsters out there who have proven to be faster than he is. If Barry could return from the Speed Force much faster than before, it would finally put this criticism to bed.
The Flash has also been mixed in its presentation of Barry's speed, with some action scenes for example apparently forgetting the full range of his abilities. If these moments could stop in Season four, that would be another big plus.