Handling [lobbies making] according to [player base size] - Dynamically?

imo the main problem this game has is;

=> Handling player base size while keeping enough in each game instance.

How to handle right lobbies limitations with a complex player-base size variation?

Number of players varies:
- along the wipe: more with the hype start, then less and less;
- along the week: peak-time/off-peak-time days;
- along the day: peak-time/off-peak-time hours per timezone;
- when arena is opened or closed;
- when a new map is realeased, or closed for maintenance;
- when the players do or don't like a patch.

Plus; this problem is a VICIOUS circle: without enough players in lobbies, it's boring, and players stop playing.

My suggestion is: PRIORITIZE THIS PROBLEM SOLVING.

Thank you!

Secondarly, I list some ideas you probably already had:
- make it more dynamic;
- i.e.; make the lobbies rules changing dynamically according to current player base;
- example: when player base is below N, dungeon is random in all mods.

Contact me if you'd like more inputs.

Cheers!