Not much. Oda is in charge or story direction, but the editor may or may not suggest things that people like or dislike. Someone brought up that without editor at the time that did Sabaody/Marineford, the Supernova wouldn't have existed, and I think they are some of the most interesting characters in the series.
But other things on a much smaller scale could been changed by an editor or suggested, mainly pacing and asking Oda to spend more time on other things (like Udon) vs. Things fans would want (battles with side characters). This we aren't 100% sure exist, but it's a possibility.
Basically new editor may help Oda refocus on some aspects of an arc to make it more entertaining or less controversial. Or they might make it worse. We won't know for a long time as we see how the next 20-40 chapters pan out.
That being said, I don't think there is much to worry about anyway. The story will still be the same now until the end, but "some" parts of the execution might be better or worse. Oda's had multiple editors for years, having 4 right now is not new.