I wish all games were like Aces High (or Aces High like all other games). Where things on the chat-bar do special things if they are prefixed by some special character. A few years ago when there were basically 3 games (plus/minus a few) every player had not seen many other games, and was motivated enough to read the manual. Today, players have played hundreds of games, and won't look at any manual. But it's not really necessary, because after having played that much, players have seen everything before. And can use everything intuitively. Everything? Except Aces High.
I wish all dot-commands could be accessed as slash-commands,
the chat-bar would open by a single press of the enter-button,
sending "message" to channel 123 could be done by typing "/123 message",
and whispering players wouldn't only work with .p player but also /w player.
On the receiving side of the chat, I wish all messages had timestamps, and messages by players on non-2xxx channels would automatically indicate the plane flown / vehicle driven / amount of beers consumed in tower.