Call of Duty is returning to the World War 2 era and that is actually a great thing. The community misses the boots on the ground gameplay after only a few games of moving into the future, but Battlefield went to the past first taking some of the Call of Duty fans. Call of Duty could return and not change anything and make a regular COD game with regular COD multiplayer, but they could do something different. They could do something so different they could change the COD franchise forever and maybe compete with Battlefield again.
Call of Duty needs to increase player count and it is very unlikely that they will now since the competitive scene has established it as six versus six sport. That still does not make this less true. Battlefield massive player count gives a player a feeling of battle and war. You have a true feeling of success when you run through any area with teammates and take it over. Battlefield 1 delivered what the competition could not do and did it well.
This is a return to what the original Call of Duty series was. There have to be bigger changes than just the things that change every year it has to be something different. The series has lost a lot of its fan base in exchange for something different that not a lot of people wanted. Also, there is a lot more competition this time around as well, especially in the multiplayer aspect.
In a way, this is Call of Duty time to make significant changes and do things they could not do originally when the game first became what it was. The series made history and has literally run through a whole timeline. The player count suggestion is a small one but it can change the whole series. That is why they should change it. Not just because it would make things different, but It is their time to do everything a little better. Maybe it will trickle down to the rest of the series. The community could only hope though.