Recently TF2 as part of the Gun Mettle Update released some commands.
- Added individual player-ready state for tournament mode
- Added new convar mp_tournament_readymode (allows tournament mode to use a per-player ready system)
- Added new convar mp_tournament_readymode_min (minimum number of players required on the server before players can toggle ready status)
- Added new convar mp_tournament_readymode_team_size (minimum number of players required to be ready per-team before the game can begin)
- Added new convar mp_tournament_readymode_countdown (the number of seconds before a match begins when both teams are ready)
This is from the Update notes from the teamfortess.com website. I am suggesting setting mp_tournament_readymode to 1 as this will change the ready up system from the "team in general" to a more MVM styled per-player system.
This would stop people from starting the game without people in as they don't have the patience to wait for people with lower spec Computers and Internet. Overall I think this would be an improvement due to the reason that I've stated.