I think May should have because She and Ash would have made a great 2 on 2 battle for each gym and any other battles. I wonder why they don't show 2 on 2 battles much in the show.
They did a few in seasons 6 and 7 but not much in seasons 8 and 9 and now they are at 3-on-3 battles and only 1 between Ash and Paul have been shown from what I have seen. I have missed a few episodes so I am not sure of any other 3-on-3 battles.