I've never had all the nations against me. Well, I've had them all attack me at the same time, but that I was because I was stretched across the map, and they were also attacking each other.
Trading cards is a bad idea. Otherwise, one player can make a lot of accounts, and have the other accounts trade good cards for bad ones in his "main" account.
The meditation rock is at the temple that has the huge cliff to get to it. The rock has a sign next to it that says that some guy meditated there and learned how to fly.
The beginning is too easy. I got 10-0 on the first game, with 3 goals scored in 4 seconds game time, and another 4 goals in less than 10 seconds. Game 2 I got 12-0.
I prefer dragons over copters, because I spam copters TOO fast, and the unit limit can't let me have that many. Once I get a high enough mana regen, I spam dragons as fast as I spam copters.