Keaton coming back is a very very big deal, so a lot of people are going to be curious for that alone since Keaton's batman defined a geek generation in the late 80s and 90s. he could easily steal the spotlight from Ezra Miller.
Hey I just figured as I am posting this. we will have at least 2 Batmans back in a film (The Flash) and a brand new reboot Batman with Rob Pattinson, all in the same year and we know both films dont have much to do with the other.
Looking at that alone I will say Batman has become too much of a safety net for DC and WB. Poor Poor Superman.