I think what Victor is saying here is that it should not be possible to start a game until all players have readied up. And I agree with this.
Right now, this would introduce a problem on headless servers, though, since - if I recall correctly - those do not allow the controlling admin to kick players. As such, a malevolent or just unresponsive player could connect to a game and not ever ready up, factually blocking this game from starting indefinitely. So if this feature was introduced, it will be necessary to also enable the controlling player to kick other players. I think so far we do not allow for this on headless servers since it would put the controlling player into the position of indefinitely blocking the headless server (and currently we only have a few headlesss servers).
If Titi will succeed in engineering and stabilizing the new headless server, hosting headless servers will become much cheaper than it is now. So we will likely have a bunch more headless servers then which will make the issue where a controlling client blocks a server irrelevant. So if we get to this point, I don't see why we could not also allow (headless server) controlling players to block players. And that would allow for requiring everyone to ready up before a game can be started - on both headless servers and standard game hosts (where a player plays and hosts at the same time).