Ash always travels with at least 2 other companions, Misty and Brock, Dawn and Brock, and now Iris and Cilan. AG gave us 4 companions with the addition of Max, and I think that the group worked a little better with 4. While Ash and May were off training or doing their own thing, Brock and Max had each other to keep them company. I think that a group of 4 adds more chemistry since all of the characters can interact in some way and it doesn't feel like anyone's left on the sidelines. Even in DP they experimented a bit by adding Barry and other characters to the group for a few episodes. Then in BW we had Bianca and N around for a new episodes.