Plus, I don't think the paying players are immune to those three problems. I've seen lag, I've seen a lot of imbalanced games, and yes anyone who happens to join a game in the last moments will only play the last moments. As I understand it, the ONLY difference with subscribe/no-subscribe is the wait time when entering a game.
Do you really want the last moments of a game to not allow in new players? And how exactly would the server know that it's the last moments? Only 1 hangar left? Carriers bombing almost 100%? Carriers almost blue or red? I've been in plenty of games where that last moment has lasted another 30 minutes. Players leave and drop out; I'd really like new players to continue to take their places. (But to your point, for balanced teams.)
Z's business is not able to buy (with money) enough servers to support (with minimum lag) all of the players who now are registered. The new pricing scheme aims to fix that. I made my own decision to pay (on top of my original one-time fee). You can decide one way or the other.
But flip for the tables for a moment. If you were a paying player, would you want to hear complaints from free players that the game is lagging? I'm not judging; I am asking YOU to judge that one.
Manfred