It’s no secret that some people simply only care about themselves, so what they do is that they will leave a match if it’s the wrong mode i.e. a mode that doesn’t progress their challenges.
This will always be an issue because people are inherently selfish. So the only way to fix this issue, and I really mean THE only way or at least the only chance you have at fixing this, is as follows;
I will be using the COD method as an example because they have nailed it with their method,
Introduce two playlists like you have now;
Quick Play and Ranked.
These two playlists will have a filter that you can open with a button press which will bring up a list of modes for these playlists like this;
(the modes and the order in which the modes appear is irrelevant, this is just for reference)
Quickplay
- Team Slayer
- Tactical Slayer
- FFA Slayer
- Fiesta
- Capture The Flag
- Oddball
- Strongholds
- Stockpile
- Total Control
Ranked
- Ranked Slayer
- Ranked CTF
- Ranked Oddball
- Ranked FFA (please 343, it’s a skill based playlist)
Now, how this will work is that when you open this filter and is presented with all these modes, you have the option to select all modes, some modes or just one mode. Based on your selection, when you search for a match you will only be placed into matches of this/these mode(s).
This means that people who want to just play for challenges are able to play exactly what they need for these challenges, thus making them happy.
This means that people who want to just play the game are able to play without having teammates leaving every single game, thus making them happy.
This means that all players get to play how they want and wont have to write angry messages on the forums about how awful this person or that person is, thus making you moderators and the devs happy.
TLDR: Give us a filter that we can pick which modes we want from for the sake of all players and your own sanity.