When the gradual reduction idea was discussed, most kingdoms still had full rooster. At the moment I don't believe there is a single full kingdom through an age, where the starting players would be same as the finishing ones. The corelation between the outcry for more invites and unstable player base is easy to spot.
Also there is no kingdom who could not kick/transfer to another kingdom/let go a few players. There are allways a few, who are less active, less skilled than the requirement, for this players the monarch could deny new age transfer, so they would be placed randomly or they could get a free, aditional move/invite.
Thus, reducing kingdom sizes can be made easily this days.
I think it would TEMPORARILY solve the lack of kingdoms issue, producing interesting results, in the way people play the game. I mean more kingdoms = more competition and that is good for the game at the moment, as Utopia starts to be completely pussyfied.
It is true that because the lower numbers a single player on top would worth more, but it is also true that the chart would be longer, with more place for the less active. Some top kingdoms would profit, others would struggle, which IMO is good as there would be a bit cleared the difference between them.
At ghetto versus top kingdom war, the less players would not significantly change anything as the ghetto would make a few less attacks / war, compared to the top kingdom who would do max possible, anyway.
On ghetto versus ghetto level nothing would change, as usually (not allways) the differences are pretty high in favor of one of them so it would not be felt much.
So what? The ones who managed to be in top 20 with less activity will be in top 25 now. The 25 players, as a rooster number is, and always was, a chosen, arbitrary number, it can change. New strategies would born, new tactics would be applied. Nothing wrong in that.
And finally, the bottom line is, that, it won't solve anything on the long term, so, in less than a year there should be a serious revival/rework of the ads and the main page and the way we get new players.
It would be still better than this, so I agree with the proposal.