That doesn't even make sense
Other than a big chase spectacle or something, what exactly could a movie do that a good Batman tv show couldn't?
at the point a good Batman tv show is on what is a $10+ 2 hour movie going to offer that people aren't just watching weekly for a total of 20+ episodes.
TV is the better format for something like Batman.
Detective work works better on tv,
Villains develop better on tv, I mean other than the highest tier all the TV cape villains are better than movie cape villains(Gotham Penguin, Riddler, Jerome, etc, S1 Reverse Flash, S1 Slade, Prometheus, Kingpin)
Gotham even showed you could get near cinematic Batman quality production design and cinematography on a network budget.
but the counter to that is even if it was an extremely successful show unless it was an anchor for a WB/AT&T streaming service, it won't benefit WB anywhere near a mildly successful movie.
Imagine S1 of Arrow with a Batman skin and not having to write around a weaker source material.
thats already more interesting than most Batman movies conceptually.
Heck imagine Mask of the Phantasm spread over a season of the series, that would be like the only way to improve on that material.
A tv series could actually give the batfamily characters the time of day.
CW's shows current quality calls it all into question but the ability and potential is always there, just depends on the quality of writing.