First off, having an experience Batman will make it easier to comprehend the character. Fans of comic and the movies of Batman have seen the character's origins on several occasions. It shouldn't be hard for audience to understand Batman's character given that the Dark Knight is in a different. Plus, being in a different scenario will be refreshing for Batman. So with this tired and weary Batman comes a new place for the character; and I think that is for the best. It will be refreshing for the character; and I think it will be easy for audiences to get reintroduce to Batman.
Despite that Batman's character might be refreshing, the difference in experience between Batman and Superman could be a problem; but what if I told you that this has happen before. Lets turn the clocks back all the way to the airing of Superman: The Animated Series. When the Man of Steel hit the small screen in the 90's, there was a time where he was joined by the Cape Crusader, who was a getting a new season to Batman:The Animated Series. Eventually the two would come together in the three part episode called World's Finest. Now here's the thing, Batman:The Animated Series was around long before Superman: The Animated Series; and World's Finest was cannon to both shows That means that the Batman in those episodes was a seasoned Dark Knight; while Superman was still getting his start. So as you can see, a seasoned Batman worked for animated pairing between the two icons, and it will work again for this upcoming film.