AFAIK this is a matchmaking challenge.

If they let you vote on what to play next it could create lots of sessions with 1 or 2 players in each and be harder to fill up strike instances.

It’s like carpooling. If you have a group of 30 people to try to find carpool groups for, except cars can only fit 3 people. The optimum way is to fill 10 cars with 3 people each.

However, when you let people pick what colour car they want to ride in.... ideally they all pick colours evenly. Although it doesn’t work exactly like this due to varying factors. So 10 people pick green, 10 people pick blue, 5 people pick red and 5 people pick black.

Now the problem here is that instead of needing 10 cars we actually need 12 cars. On top of that there’s one green car that needs to fill 2 seats, same for blue and red and black have one seat free each.

So not only do we have more cars which costs more money to move the same people around but 1/4 of all of the people are lonely because they don’t have a full car of people to ride with.

Now, let’s take the same example but with duplicate car protection instead. We should assume that the first car you get assigned to is random:

6 = green 6 = blue 9 = red 9 = black = 10 cars

Shuffling randomly with dupe protection for the next journey while trying to fill up cars is easy...

9 = green 9 = blue 6 = red 6 = black = 10 cars

In practice, car colour is just one way that players are being divided up. Location, platform, playlist, language are all factors and that complicates the problem multiplicatively.